Remove usage of base::make_span(): base/

Replace with span() CTAD use, or more targeted helpers.

Also removes some unnecessary uses of base::.

Bug: 341907909
Change-Id: I521bbcd1bc6aa622be75093fc82a02543cb31dc7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6052443
Auto-Submit: Peter Kasting <[email protected]>
Reviewed-by: Tom Sepez <[email protected]>
Commit-Queue: Peter Kasting <[email protected]>
Code-Coverage: [email protected] <[email protected]>
Commit-Queue: Tom Sepez <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1388924}
diff --git a/base/allocator/miracle_parameter.h b/base/allocator/miracle_parameter.h
index 68716789..7a5d23b 100644
--- a/base/allocator/miracle_parameter.h
+++ b/base/allocator/miracle_parameter.h
@@ -166,7 +166,7 @@
                                    default_value, type, options)            \
   type function_name() {                                                    \
     static const type value = miracle_parameter::GetMiracleParameterAsEnum( \
-        feature, param_name, default_value, base::make_span(options));      \
+        feature, param_name, default_value, base::span(options));           \
     return value;                                                           \
   }
 
diff --git a/base/allocator/partition_alloc_support.cc b/base/allocator/partition_alloc_support.cc
index 442fcb0..878a9f5c 100644
--- a/base/allocator/partition_alloc_support.cc
+++ b/base/allocator/partition_alloc_support.cc
@@ -674,9 +674,9 @@
       LOG(ERROR) << debug::StackTrace(
                         // This call truncates the `nullptr` tail of the stack
                         // trace (see the `is_partitioned` CHECK above).
-                        make_span(raw_stack_trace.begin(),
-                                  ranges::partition_point(
-                                      raw_stack_trace, is_frame_ptr_not_null)))
+                        span(raw_stack_trace.begin(),
+                             ranges::partition_point(raw_stack_trace,
+                                                     is_frame_ptr_not_null)))
                  << "\n";
     }
 #else
diff --git a/base/apple/foundation_util.h b/base/apple/foundation_util.h
index 66c092f..44a7b73 100644
--- a/base/apple/foundation_util.h
+++ b/base/apple/foundation_util.h
@@ -308,7 +308,7 @@
 inline span<const uint8_t> NSDataToSpan(NSData* data) {
   // SAFETY: `NSData` guarantees that `bytes` is exactly `length` in size.
   return UNSAFE_BUFFERS(
-      make_span(static_cast<const uint8_t*>(data.bytes), data.length));
+      span(static_cast<const uint8_t*>(data.bytes), size_t{data.length}));
 }
 
 // Returns a mutable `base::span<uint8_t>` pointing to the memory owned by
@@ -320,7 +320,7 @@
   // SAFETY: `NSMutableData` guarantees that `mutableBytes` is exactly `length`
   // in size.
   return UNSAFE_BUFFERS(
-      make_span(static_cast<uint8_t*>(data.mutableBytes), data.length));
+      span(static_cast<uint8_t*>(data.mutableBytes), size_t{data.length}));
 }
 
 #endif  // defined(__OBJC__)
diff --git a/base/apple/foundation_util_unittest.mm b/base/apple/foundation_util_unittest.mm
index 55ffec30..08ea54e 100644
--- a/base/apple/foundation_util_unittest.mm
+++ b/base/apple/foundation_util_unittest.mm
@@ -521,17 +521,17 @@
   {
     ScopedCFTypeRef<CFDataRef> data(
         CFDataCreate(nullptr, buffer, sizeof(buffer)));
-    span<const uint8_t> span = CFDataToSpan(data.get());
-    EXPECT_EQ(make_span(buffer), span);
-    EXPECT_THAT(span, ElementsAreArray(buffer));
+    span<const uint8_t> data_span = CFDataToSpan(data.get());
+    EXPECT_EQ(span(buffer), data_span);
+    EXPECT_THAT(data_span, ElementsAreArray(buffer));
   }
 
   {
     ScopedCFTypeRef<CFMutableDataRef> data(CFDataCreateMutable(nullptr, 0));
     CFDataAppendBytes(data.get(), buffer, sizeof(buffer));
-    span<uint8_t> span = CFMutableDataToSpan(data.get());
-    EXPECT_EQ(make_span(buffer), span);
-    span[0] = 123;
+    span<uint8_t> data_span = CFMutableDataToSpan(data.get());
+    EXPECT_EQ(span(buffer), data_span);
+    data_span[0] = 123;
     EXPECT_EQ(CFDataGetBytePtr(data.get())[0], 123);
   }
 }
diff --git a/base/base64_unittest.cc b/base/base64_unittest.cc
index 948bf622..bff8eee 100644
--- a/base/base64_unittest.cc
+++ b/base/base64_unittest.cc
@@ -144,7 +144,7 @@
   // crash. This test is only meaningful because `EXPECT_CHECK_DEATH` looks for
   // a `CHECK`-based failure.
   uint8_t b;
-  auto large_span = base::make_span(&b, MODP_B64_MAX_INPUT_LEN + 1);
+  auto large_span = span(&b, MODP_B64_MAX_INPUT_LEN + 1);
   EXPECT_CHECK_DEATH(Base64Encode(large_span));
 
   std::string output = "PREFIX";
diff --git a/base/containers/adapters_unittest.cc b/base/containers/adapters_unittest.cc
index 6c3f334c..483fd75 100644
--- a/base/containers/adapters_unittest.cc
+++ b/base/containers/adapters_unittest.cc
@@ -72,12 +72,12 @@
     static_assert(std::ranges::sized_range<decltype(base::Reversed(s))>);
     static_assert(std::ranges::borrowed_range<decltype(base::Reversed(s))>);
 
-    auto make_span = [] { return base::span<int>(); };
-    static_assert(std::ranges::range<decltype(base::Reversed(make_span()))>);
+    auto rvalue_span = [] { return base::span<int>(); };
+    static_assert(std::ranges::range<decltype(base::Reversed(rvalue_span()))>);
     static_assert(
-        std::ranges::sized_range<decltype(base::Reversed(make_span()))>);
+        std::ranges::sized_range<decltype(base::Reversed(rvalue_span()))>);
     static_assert(
-        std::ranges::borrowed_range<decltype(base::Reversed(make_span()))>);
+        std::ranges::borrowed_range<decltype(base::Reversed(rvalue_span()))>);
   }
 
   {
diff --git a/base/containers/span_nocompile.nc b/base/containers/span_nocompile.nc
index 11ccb608..fffa95f 100644
--- a/base/containers/span_nocompile.nc
+++ b/base/containers/span_nocompile.nc
@@ -136,12 +136,12 @@
 // as_writable_bytes should not be possible for a const container.
 void AsWritableBytesWithConstContainerDisallowed() {
   const std::vector<int> v = {1, 2, 3};
-  span<uint8_t> bytes = as_writable_bytes(make_span(v));  // expected-error {{no matching function for call to 'as_writable_bytes'}}
+  span<uint8_t> bytes = as_writable_bytes(span(v));  // expected-error {{no matching function for call to 'as_writable_bytes'}}
 }
 
 void ConstVectorDeducesAsConstSpan() {
   const std::vector<int> v;
-  span<int> s = make_span(v);  // expected-error-re@*:* {{no viable conversion from 'span<{{.*}}, [...]>' to 'span<int, [...]>'}}
+  span<int> s = span(v);  // expected-error-re@*:* {{no viable conversion from 'span<{{.*}}, [...]>' to 'span<int, [...]>'}}
 }
 
 // A span can only be constructed from a range rvalue when the element type is
diff --git a/base/containers/span_unittest.cc b/base/containers/span_unittest.cc
index eff4e8e..896b198 100644
--- a/base/containers/span_unittest.cc
+++ b/base/containers/span_unittest.cc
@@ -1637,7 +1637,7 @@
 TEST(SpanTest, AsBytes) {
   {
     constexpr int kArray[] = {2, 3, 5, 7, 11, 13};
-    auto bytes_span = as_bytes(make_span(kArray));
+    auto bytes_span = as_bytes(span(kArray));
     static_assert(std::is_same_v<decltype(bytes_span),
                                  span<const uint8_t, sizeof(kArray)>>);
     EXPECT_EQ(reinterpret_cast<const uint8_t*>(kArray), bytes_span.data());
@@ -1691,7 +1691,7 @@
 TEST(SpanTest, AsChars) {
   {
     constexpr int kArray[] = {2, 3, 5, 7, 11, 13};
-    auto chars_span = as_chars(make_span(kArray));
+    auto chars_span = as_chars(span(kArray));
     static_assert(
         std::is_same_v<decltype(chars_span), span<const char, sizeof(kArray)>>);
     EXPECT_EQ(reinterpret_cast<const char*>(kArray), chars_span.data());
@@ -2187,11 +2187,11 @@
 TEST(SpanTest, CopyFrom) {
   int arr[] = {1, 2, 3};
   span<int, 0> empty_static_span;
-  span<int, 3> static_span = make_span(arr);
+  span<int, 3> static_span = span(arr);
 
   std::vector<int> vec = {4, 5, 6};
   span<int> empty_dynamic_span;
-  span<int> dynamic_span = make_span(vec);
+  span<int> dynamic_span = span(vec);
 
   // Handle empty cases gracefully.
   // Dynamic size to static size requires an explicit conversion.
@@ -2321,11 +2321,11 @@
 TEST(SpanTest, CopyFromNonoverlapping) {
   int arr[] = {1, 2, 3};
   span<int, 0> empty_static_span;
-  span<int, 3> static_span = make_span(arr);
+  span<int, 3> static_span = span(arr);
 
   std::vector<int> vec = {4, 5, 6};
   span<int> empty_dynamic_span;
-  span<int> dynamic_span = make_span(vec);
+  span<int> dynamic_span = span(vec);
 
   // Handle empty cases gracefully.
   UNSAFE_BUFFERS({
@@ -2366,10 +2366,10 @@
 
 TEST(SpanTest, CopyFromConversion) {
   int arr[] = {1, 2, 3};
-  span<int, 3> static_span = make_span(arr);
+  span<int, 3> static_span = span(arr);
 
   std::vector<int> vec = {4, 5, 6};
-  span<int> dynamic_span = make_span(vec);
+  span<int> dynamic_span = span(vec);
 
   std::vector convert_from = {7, 8, 9};
   static_span.copy_from(convert_from);
@@ -2457,11 +2457,11 @@
 TEST(SpanTest, SplitAt) {
   int arr[] = {1, 2, 3};
   span<int, 0> empty_static_span;
-  span<int, 3> static_span = make_span(arr);
+  span<int, 3> static_span = span(arr);
 
   std::vector<int> vec = {4, 5, 6};
   span<int> empty_dynamic_span;
-  span<int> dynamic_span = make_span(vec);
+  span<int> dynamic_span = span(vec);
 
   {
     auto [left, right] = empty_static_span.split_at(0u);
diff --git a/base/files/file_unittest.cc b/base/files/file_unittest.cc
index d5f7e0c5..057f0d5 100644
--- a/base/files/file_unittest.cc
+++ b/base/files/file_unittest.cc
@@ -35,11 +35,10 @@
 #include "base/test/gtest_util.h"
 #endif
 
-using base::File;
-using base::FilePath;
+namespace base {
 
 TEST(FileTest, Create) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("create_file_1");
 
@@ -47,35 +46,35 @@
     // Don't create a File at all.
     File file;
     EXPECT_FALSE(file.IsValid());
-    EXPECT_EQ(base::File::FILE_ERROR_FAILED, file.error_details());
+    EXPECT_EQ(File::FILE_ERROR_FAILED, file.error_details());
 
-    File file2(base::File::FILE_ERROR_TOO_MANY_OPENED);
+    File file2(File::FILE_ERROR_TOO_MANY_OPENED);
     EXPECT_FALSE(file2.IsValid());
-    EXPECT_EQ(base::File::FILE_ERROR_TOO_MANY_OPENED, file2.error_details());
+    EXPECT_EQ(File::FILE_ERROR_TOO_MANY_OPENED, file2.error_details());
   }
 
   {
     // Open a file that doesn't exist.
-    File file(file_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
+    File file(file_path, File::FLAG_OPEN | File::FLAG_READ);
     EXPECT_FALSE(file.IsValid());
-    EXPECT_EQ(base::File::FILE_ERROR_NOT_FOUND, file.error_details());
-    EXPECT_EQ(base::File::FILE_ERROR_NOT_FOUND, base::File::GetLastFileError());
+    EXPECT_EQ(File::FILE_ERROR_NOT_FOUND, file.error_details());
+    EXPECT_EQ(File::FILE_ERROR_NOT_FOUND, File::GetLastFileError());
   }
 
   {
     // Open or create a file.
-    File file(file_path, base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_READ);
+    File file(file_path, File::FLAG_OPEN_ALWAYS | File::FLAG_READ);
     EXPECT_TRUE(file.IsValid());
     EXPECT_TRUE(file.created());
-    EXPECT_EQ(base::File::FILE_OK, file.error_details());
+    EXPECT_EQ(File::FILE_OK, file.error_details());
   }
 
   {
     // Open an existing file.
-    File file(file_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
+    File file(file_path, File::FLAG_OPEN | File::FLAG_READ);
     EXPECT_TRUE(file.IsValid());
     EXPECT_FALSE(file.created());
-    EXPECT_EQ(base::File::FILE_OK, file.error_details());
+    EXPECT_EQ(File::FILE_OK, file.error_details());
 
     // This time verify closing the file.
     file.Close();
@@ -85,10 +84,10 @@
   {
     // Open an existing file through Initialize
     File file;
-    file.Initialize(file_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
+    file.Initialize(file_path, File::FLAG_OPEN | File::FLAG_READ);
     EXPECT_TRUE(file.IsValid());
     EXPECT_FALSE(file.created());
-    EXPECT_EQ(base::File::FILE_OK, file.error_details());
+    EXPECT_EQ(File::FILE_OK, file.error_details());
 
     // This time verify closing the file.
     file.Close();
@@ -97,97 +96,91 @@
 
   {
     // Create a file that exists.
-    File file(file_path, base::File::FLAG_CREATE | base::File::FLAG_READ);
+    File file(file_path, File::FLAG_CREATE | File::FLAG_READ);
     EXPECT_FALSE(file.IsValid());
     EXPECT_FALSE(file.created());
-    EXPECT_EQ(base::File::FILE_ERROR_EXISTS, file.error_details());
-    EXPECT_EQ(base::File::FILE_ERROR_EXISTS, base::File::GetLastFileError());
+    EXPECT_EQ(File::FILE_ERROR_EXISTS, file.error_details());
+    EXPECT_EQ(File::FILE_ERROR_EXISTS, File::GetLastFileError());
   }
 
   {
     // Create or overwrite a file.
-    File file(file_path,
-              base::File::FLAG_CREATE_ALWAYS | base::File::FLAG_WRITE);
+    File file(file_path, File::FLAG_CREATE_ALWAYS | File::FLAG_WRITE);
     EXPECT_TRUE(file.IsValid());
     EXPECT_TRUE(file.created());
-    EXPECT_EQ(base::File::FILE_OK, file.error_details());
+    EXPECT_EQ(File::FILE_OK, file.error_details());
   }
 
   {
     // Create a delete-on-close file.
     file_path = temp_dir.GetPath().AppendASCII("create_file_2");
-    File file(file_path,
-              base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_READ |
-                  base::File::FLAG_DELETE_ON_CLOSE);
+    File file(file_path, File::FLAG_OPEN_ALWAYS | File::FLAG_READ |
+                             File::FLAG_DELETE_ON_CLOSE);
     EXPECT_TRUE(file.IsValid());
     EXPECT_TRUE(file.created());
-    EXPECT_EQ(base::File::FILE_OK, file.error_details());
+    EXPECT_EQ(File::FILE_OK, file.error_details());
   }
 
-  EXPECT_FALSE(base::PathExists(file_path));
+  EXPECT_FALSE(PathExists(file_path));
 }
 
 TEST(FileTest, SelfSwap) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("create_file_1");
-  File file(file_path,
-            base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_DELETE_ON_CLOSE);
+  File file(file_path, File::FLAG_OPEN_ALWAYS | File::FLAG_DELETE_ON_CLOSE);
   std::swap(file, file);
   EXPECT_TRUE(file.IsValid());
 }
 
 TEST(FileTest, Async) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("create_file");
 
   {
-    File file(file_path, base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_ASYNC);
+    File file(file_path, File::FLAG_OPEN_ALWAYS | File::FLAG_ASYNC);
     EXPECT_TRUE(file.IsValid());
     EXPECT_TRUE(file.async());
   }
 
   {
-    File file(file_path, base::File::FLAG_OPEN_ALWAYS);
+    File file(file_path, File::FLAG_OPEN_ALWAYS);
     EXPECT_TRUE(file.IsValid());
     EXPECT_FALSE(file.async());
   }
 }
 
 TEST(FileTest, DeleteOpenFile) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("create_file_1");
 
   // Create a file.
-  File file(file_path, base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_READ |
-                           base::File::FLAG_WIN_SHARE_DELETE);
+  File file(file_path, File::FLAG_OPEN_ALWAYS | File::FLAG_READ |
+                           File::FLAG_WIN_SHARE_DELETE);
   EXPECT_TRUE(file.IsValid());
   EXPECT_TRUE(file.created());
-  EXPECT_EQ(base::File::FILE_OK, file.error_details());
+  EXPECT_EQ(File::FILE_OK, file.error_details());
 
   // Open an existing file and mark it as delete on close.
-  File same_file(file_path,
-                 base::File::FLAG_OPEN | base::File::FLAG_DELETE_ON_CLOSE |
-                     base::File::FLAG_READ);
+  File same_file(file_path, File::FLAG_OPEN | File::FLAG_DELETE_ON_CLOSE |
+                                File::FLAG_READ);
   EXPECT_TRUE(file.IsValid());
   EXPECT_FALSE(same_file.created());
-  EXPECT_EQ(base::File::FILE_OK, same_file.error_details());
+  EXPECT_EQ(File::FILE_OK, same_file.error_details());
 
   // Close both handles and check that the file is gone.
   file.Close();
   same_file.Close();
-  EXPECT_FALSE(base::PathExists(file_path));
+  EXPECT_FALSE(PathExists(file_path));
 }
 
 TEST(FileTest, ReadWrite) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("read_write_file");
-  File file(file_path,
-            base::File::FLAG_CREATE | base::File::FLAG_READ |
-                base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   ASSERT_TRUE(file.IsValid());
 
   char data_to_write[] = "test";
@@ -214,8 +207,9 @@
   const int kPartialReadOffset = 1;
   bytes_read = file.Read(kPartialReadOffset, data_read_1, kTestDataSize);
   EXPECT_EQ(kTestDataSize - kPartialReadOffset, bytes_read);
-  for (int i = 0; i < bytes_read; i++)
+  for (int i = 0; i < bytes_read; i++) {
     EXPECT_EQ(data_to_write[i + kPartialReadOffset], data_read_1[i]);
+  }
 
   // Read 0 bytes.
   bytes_read = file.Read(0, data_read_1, 0);
@@ -224,12 +218,13 @@
   // Read the entire file.
   bytes_read = file.Read(0, data_read_1, kTestDataSize);
   EXPECT_EQ(kTestDataSize, bytes_read);
-  for (int i = 0; i < bytes_read; i++)
+  for (int i = 0; i < bytes_read; i++) {
     EXPECT_EQ(data_to_write[i], data_read_1[i]);
+  }
 
   // Read again, but using the trivial native wrapper.
   std::optional<size_t> maybe_bytes_read =
-      file.ReadNoBestEffort(0, base::as_writable_byte_span(data_read_1)
+      file.ReadNoBestEffort(0, as_writable_byte_span(data_read_1)
                                    .first(static_cast<size_t>(kTestDataSize)));
   ASSERT_TRUE(maybe_bytes_read.has_value());
   EXPECT_LE(maybe_bytes_read.value(), static_cast<size_t>(kTestDataSize));
@@ -240,8 +235,8 @@
   // Write past the end of the file.
   const int kOffsetBeyondEndOfFile = 10;
   const int kPartialWriteLength = 2;
-  bytes_written = file.Write(kOffsetBeyondEndOfFile,
-                             data_to_write, kPartialWriteLength);
+  bytes_written =
+      file.Write(kOffsetBeyondEndOfFile, data_to_write, kPartialWriteLength);
   EXPECT_EQ(kPartialWriteLength, bytes_written);
 
   // Make sure the file was extended.
@@ -253,30 +248,32 @@
   char data_read_2[32];
   bytes_read = file.Read(0, data_read_2, static_cast<int>(file_size.value()));
   EXPECT_EQ(file_size, bytes_read);
-  for (int i = 0; i < kTestDataSize; i++)
+  for (int i = 0; i < kTestDataSize; i++) {
     EXPECT_EQ(data_to_write[i], data_read_2[i]);
-  for (int i = kTestDataSize; i < kOffsetBeyondEndOfFile; i++)
+  }
+  for (int i = kTestDataSize; i < kOffsetBeyondEndOfFile; i++) {
     EXPECT_EQ(0, data_read_2[i]);
-  for (int i = kOffsetBeyondEndOfFile; i < file_size; i++)
+  }
+  for (int i = kOffsetBeyondEndOfFile; i < file_size; i++) {
     EXPECT_EQ(data_to_write[i - kOffsetBeyondEndOfFile], data_read_2[i]);
+  }
 }
 
 TEST(FileTest, ReadWriteSpans) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("read_write_file");
-  File file(file_path, base::File::FLAG_CREATE | base::File::FLAG_READ |
-                           base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   ASSERT_TRUE(file.IsValid());
 
   // Write 0 bytes to the file.
-  std::optional<size_t> bytes_written = file.Write(0, base::span<uint8_t>());
+  std::optional<size_t> bytes_written = file.Write(0, span<uint8_t>());
   ASSERT_TRUE(bytes_written.has_value());
   EXPECT_EQ(0u, bytes_written.value());
 
   // Write "test" to the file.
   std::string data_to_write("test");
-  bytes_written = file.Write(0, base::as_byte_span(data_to_write));
+  bytes_written = file.Write(0, as_byte_span(data_to_write));
   ASSERT_TRUE(bytes_written.has_value());
   EXPECT_EQ(data_to_write.size(), bytes_written.value());
 
@@ -297,7 +294,7 @@
   }
 
   // Read 0 bytes.
-  bytes_read = file.Read(0, base::span<uint8_t>());
+  bytes_read = file.Read(0, span<uint8_t>());
   ASSERT_TRUE(bytes_read.has_value());
   EXPECT_EQ(0u, bytes_read.value());
 
@@ -314,7 +311,7 @@
   const size_t kPartialWriteLength = 2;
   bytes_written =
       file.Write(kOffsetBeyondEndOfFile,
-                 base::as_byte_span(data_to_write).first(kPartialWriteLength));
+                 as_byte_span(data_to_write).first(kPartialWriteLength));
   ASSERT_TRUE(bytes_written.has_value());
   EXPECT_EQ(kPartialWriteLength, bytes_written.value());
 
@@ -348,7 +345,7 @@
 #endif
   EXPECT_EQ(File::FILE_ERROR_ACCESS_DENIED, File::GetLastFileError());
 
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   EXPECT_TRUE(temp_dir.CreateUniqueTempDir());
 
   FilePath nonexistent_path(temp_dir.GetPath().AppendASCII("nonexistent"));
@@ -360,10 +357,10 @@
 }
 
 TEST(FileTest, Append) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("append_file");
-  File file(file_path, base::File::FLAG_CREATE | base::File::FLAG_APPEND);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_APPEND);
   ASSERT_TRUE(file.IsValid());
 
   char data_to_write[] = "test";
@@ -382,9 +379,7 @@
   EXPECT_EQ(kTestDataSize, bytes_written);
 
   file.Close();
-  File file2(file_path,
-             base::File::FLAG_OPEN | base::File::FLAG_READ |
-                 base::File::FLAG_APPEND);
+  File file2(file_path, File::FLAG_OPEN | File::FLAG_READ | File::FLAG_APPEND);
   ASSERT_TRUE(file2.IsValid());
 
   // Test passing the file around.
@@ -401,23 +396,21 @@
 
   // Read the entire file.
   char data_read_1[32];
-  int bytes_read = file.Read(0, data_read_1,
-                             kTestDataSize + kAppendDataSize);
+  int bytes_read = file.Read(0, data_read_1, kTestDataSize + kAppendDataSize);
   EXPECT_EQ(kTestDataSize + kAppendDataSize, bytes_read);
-  for (int i = 0; i < kTestDataSize; i++)
+  for (int i = 0; i < kTestDataSize; i++) {
     EXPECT_EQ(data_to_write[i], data_read_1[i]);
-  for (int i = 0; i < kAppendDataSize; i++)
+  }
+  for (int i = 0; i < kAppendDataSize; i++) {
     EXPECT_EQ(append_data_to_write[i], data_read_1[kTestDataSize + i]);
+  }
 }
 
-
 TEST(FileTest, Length) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("truncate_file");
-  File file(file_path,
-            base::File::FLAG_CREATE | base::File::FLAG_READ |
-                base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   ASSERT_TRUE(file.IsValid());
   EXPECT_EQ(0, file.GetLength());
 
@@ -439,10 +432,12 @@
   char data_read[32];
   int bytes_read = file.Read(0, data_read, static_cast<int>(file_size.value()));
   EXPECT_EQ(file_size, bytes_read);
-  for (int i = 0; i < kTestDataSize; i++)
+  for (int i = 0; i < kTestDataSize; i++) {
     EXPECT_EQ(data_to_write[i], data_read[i]);
-  for (int i = kTestDataSize; i < file_size; i++)
+  }
+  for (int i = kTestDataSize; i < file_size; i++) {
     EXPECT_EQ(0, data_read[i]);
+  }
 
   // Truncate the file.
   const int kTruncatedFileLength = 2;
@@ -470,11 +465,10 @@
   EXPECT_EQ(kBigFileLength, file_size.value());
 #endif
 
-  // Close the file and reopen with base::File::FLAG_CREATE_ALWAYS, and make
+  // Close the file and reopen with File::FLAG_CREATE_ALWAYS, and make
   // sure the file is empty (old file was overridden).
   file.Close();
-  file.Initialize(file_path,
-                  base::File::FLAG_CREATE_ALWAYS | base::File::FLAG_WRITE);
+  file.Initialize(file_path, File::FLAG_CREATE_ALWAYS | File::FLAG_WRITE);
   EXPECT_EQ(0, file.GetLength());
 }
 
@@ -484,27 +478,26 @@
 #else
 TEST(FileTest, DISABLED_TouchGetInfo) {
 #endif
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   File file(temp_dir.GetPath().AppendASCII("touch_get_info_file"),
-            base::File::FLAG_CREATE | base::File::FLAG_WRITE |
-                base::File::FLAG_WRITE_ATTRIBUTES);
+            File::FLAG_CREATE | File::FLAG_WRITE | File::FLAG_WRITE_ATTRIBUTES);
   ASSERT_TRUE(file.IsValid());
 
   // Get info for a newly created file.
-  base::File::Info info;
+  File::Info info;
   EXPECT_TRUE(file.GetInfo(&info));
 
   // Add 2 seconds to account for possible rounding errors on
   // filesystems that use a 1s or 2s timestamp granularity.
-  base::Time now = base::Time::Now() + base::Seconds(2);
+  Time now = Time::Now() + Seconds(2);
   EXPECT_EQ(0, info.size);
   EXPECT_FALSE(info.is_directory);
   EXPECT_FALSE(info.is_symbolic_link);
   EXPECT_LE(info.last_accessed.ToInternalValue(), now.ToInternalValue());
   EXPECT_LE(info.last_modified.ToInternalValue(), now.ToInternalValue());
   EXPECT_LE(info.creation_time.ToInternalValue(), now.ToInternalValue());
-  base::Time creation_time = info.creation_time;
+  Time creation_time = info.creation_time;
 
   // Write "test" to the file.
   char data[] = "test";
@@ -516,8 +509,8 @@
   // It's best to add values that are multiples of 2 (in seconds)
   // to the current last_accessed and last_modified times, because
   // FATxx uses a 2s timestamp granularity.
-  base::Time new_last_accessed = info.last_accessed + base::Seconds(234);
-  base::Time new_last_modified = info.last_modified + base::Minutes(567);
+  Time new_last_accessed = info.last_accessed + Seconds(234);
+  Time new_last_modified = info.last_modified + Minutes(567);
 
   EXPECT_TRUE(file.SetTimes(new_last_accessed, new_last_modified));
 
@@ -547,19 +540,18 @@
 // Test we can retrieve the file's creation time through File::GetInfo().
 TEST(FileTest, GetInfoForCreationTime) {
   int64_t before_creation_time_s =
-      base::Time::Now().ToDeltaSinceWindowsEpoch().InSeconds();
+      Time::Now().ToDeltaSinceWindowsEpoch().InSeconds();
 
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("test_file");
-  File file(file_path, base::File::FLAG_CREATE | base::File::FLAG_READ |
-                           base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   EXPECT_TRUE(file.IsValid());
 
   int64_t after_creation_time_s =
-      base::Time::Now().ToDeltaSinceWindowsEpoch().InSeconds();
+      Time::Now().ToDeltaSinceWindowsEpoch().InSeconds();
 
-  base::File::Info info;
+  File::Info info;
   EXPECT_TRUE(file.GetInfo(&info));
   EXPECT_GE(info.creation_time.ToDeltaSinceWindowsEpoch().InSeconds(),
             before_creation_time_s);
@@ -568,20 +560,18 @@
 }
 
 TEST(FileTest, ReadAtCurrentPosition) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path =
       temp_dir.GetPath().AppendASCII("read_at_current_position");
-  File file(file_path,
-            base::File::FLAG_CREATE | base::File::FLAG_READ |
-                base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   EXPECT_TRUE(file.IsValid());
 
   const char kData[] = "test";
   const int kDataSize = sizeof(kData) - 1;
   EXPECT_EQ(kDataSize, file.Write(0, kData, kDataSize));
 
-  EXPECT_EQ(0, file.Seek(base::File::FROM_BEGIN, 0));
+  EXPECT_EQ(0, file.Seek(File::FROM_BEGIN, 0));
 
   char buffer[kDataSize];
   int first_chunk_size = kDataSize / 2;
@@ -593,45 +583,36 @@
 }
 
 TEST(FileTest, ReadAtCurrentPositionSpans) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path =
       temp_dir.GetPath().AppendASCII("read_at_current_position");
-  File file(file_path, base::File::FLAG_CREATE | base::File::FLAG_READ |
-                           base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   EXPECT_TRUE(file.IsValid());
 
   std::string data("test");
-  std::optional<size_t> result = file.Write(0, base::as_byte_span(data));
+  std::optional<size_t> result = file.Write(0, as_byte_span(data));
   ASSERT_TRUE(result.has_value());
   EXPECT_EQ(data.size(), result.value());
 
-  EXPECT_EQ(0, file.Seek(base::File::FROM_BEGIN, 0));
+  EXPECT_EQ(0, file.Seek(File::FROM_BEGIN, 0));
 
   uint8_t buffer[4];
   size_t first_chunk_size = 2;
-  result =
-      file.ReadAtCurrentPos(base::make_span(buffer).first(first_chunk_size));
-  ASSERT_TRUE(result.has_value());
-  EXPECT_EQ(first_chunk_size, result.value());
-
-  result =
-      file.ReadAtCurrentPos(base::make_span(buffer).subspan(first_chunk_size));
-  ASSERT_TRUE(result.has_value());
-  EXPECT_EQ(first_chunk_size, result.value());
+  const auto [chunk1, chunk2] = span(buffer).split_at(first_chunk_size);
+  EXPECT_EQ(chunk1.size(), file.ReadAtCurrentPos(chunk1));
+  EXPECT_EQ(chunk2.size(), file.ReadAtCurrentPos(chunk2));
   for (size_t i = 0; i < data.size(); i++) {
     EXPECT_EQ(data[i], static_cast<char>(buffer[i]));
   }
 }
 
 TEST(FileTest, WriteAtCurrentPosition) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path =
       temp_dir.GetPath().AppendASCII("write_at_current_position");
-  File file(file_path,
-            base::File::FLAG_CREATE | base::File::FLAG_READ |
-                base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   EXPECT_TRUE(file.IsValid());
 
   const char kData[] = "test";
@@ -649,23 +630,21 @@
 }
 
 TEST(FileTest, WriteAtCurrentPositionSpans) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path =
       temp_dir.GetPath().AppendASCII("write_at_current_position");
-  File file(file_path, base::File::FLAG_CREATE | base::File::FLAG_READ |
-                           base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   EXPECT_TRUE(file.IsValid());
 
   std::string data("test");
   size_t first_chunk_size = data.size() / 2;
   std::optional<size_t> result =
-      file.WriteAtCurrentPos(base::as_byte_span(data).first(first_chunk_size));
+      file.WriteAtCurrentPos(as_byte_span(data).first(first_chunk_size));
   ASSERT_TRUE(result.has_value());
   EXPECT_EQ(first_chunk_size, result.value());
 
-  result = file.WriteAtCurrentPos(
-      base::as_byte_span(data).subspan(first_chunk_size));
+  result = file.WriteAtCurrentPos(as_byte_span(data).subspan(first_chunk_size));
   ASSERT_TRUE(result.has_value());
   EXPECT_EQ(first_chunk_size, result.value());
 
@@ -676,29 +655,26 @@
 }
 
 TEST(FileTest, Seek) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("seek_file");
-  File file(file_path,
-            base::File::FLAG_CREATE | base::File::FLAG_READ |
-                base::File::FLAG_WRITE);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE);
   ASSERT_TRUE(file.IsValid());
 
   const int64_t kOffset = 10;
-  EXPECT_EQ(kOffset, file.Seek(base::File::FROM_BEGIN, kOffset));
-  EXPECT_EQ(2 * kOffset, file.Seek(base::File::FROM_CURRENT, kOffset));
-  EXPECT_EQ(kOffset, file.Seek(base::File::FROM_CURRENT, -kOffset));
+  EXPECT_EQ(kOffset, file.Seek(File::FROM_BEGIN, kOffset));
+  EXPECT_EQ(2 * kOffset, file.Seek(File::FROM_CURRENT, kOffset));
+  EXPECT_EQ(kOffset, file.Seek(File::FROM_CURRENT, -kOffset));
   EXPECT_TRUE(file.SetLength(kOffset * 2));
-  EXPECT_EQ(kOffset, file.Seek(base::File::FROM_END, -kOffset));
+  EXPECT_EQ(kOffset, file.Seek(File::FROM_END, -kOffset));
 }
 
 TEST(FileTest, Duplicate) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
-  File file(file_path,(base::File::FLAG_CREATE |
-                       base::File::FLAG_READ |
-                       base::File::FLAG_WRITE));
+  File file(file_path,
+            (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE));
   ASSERT_TRUE(file.IsValid());
 
   File file2(file.Duplicate());
@@ -708,11 +684,11 @@
   static const char kData[] = "now is a good time.";
   static const int kDataLen = sizeof(kData) - 1;
 
-  ASSERT_EQ(0, file.Seek(base::File::FROM_CURRENT, 0));
-  ASSERT_EQ(0, file2.Seek(base::File::FROM_CURRENT, 0));
+  ASSERT_EQ(0, file.Seek(File::FROM_CURRENT, 0));
+  ASSERT_EQ(0, file2.Seek(File::FROM_CURRENT, 0));
   ASSERT_EQ(kDataLen, file.WriteAtCurrentPos(kData, kDataLen));
-  ASSERT_EQ(kDataLen, file.Seek(base::File::FROM_CURRENT, 0));
-  ASSERT_EQ(kDataLen, file2.Seek(base::File::FROM_CURRENT, 0));
+  ASSERT_EQ(kDataLen, file.Seek(File::FROM_CURRENT, 0));
+  ASSERT_EQ(kDataLen, file2.Seek(File::FROM_CURRENT, 0));
   file.Close();
   char buf[kDataLen];
   ASSERT_EQ(kDataLen, file2.Read(0, &buf[0], kDataLen));
@@ -720,30 +696,27 @@
 }
 
 TEST(FileTest, DuplicateDeleteOnClose) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
-  File file(file_path,(base::File::FLAG_CREATE |
-                       base::File::FLAG_READ |
-                       base::File::FLAG_WRITE |
-                       base::File::FLAG_DELETE_ON_CLOSE));
+  File file(file_path, (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+                        File::FLAG_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
   File file2(file.Duplicate());
   ASSERT_TRUE(file2.IsValid());
   file.Close();
   file2.Close();
-  ASSERT_FALSE(base::PathExists(file_path));
+  ASSERT_FALSE(PathExists(file_path));
 }
 
 #if BUILDFLAG(ENABLE_BASE_TRACING)
 TEST(FileTest, TracedValueSupport) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
-  File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_DELETE_ON_CLOSE));
+  File file(file_path, (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+                        File::FLAG_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
 
   EXPECT_EQ(perfetto::TracedValueToString(file),
@@ -758,12 +731,11 @@
 #define MAYBE_WriteDataToLargeOffset WriteDataToLargeOffset
 #endif
 TEST(FileTest, MAYBE_WriteDataToLargeOffset) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
-  File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_DELETE_ON_CLOSE));
+  File file(file_path, (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+                        File::FLAG_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
 
   const char kData[] = "this file is sparse.";
@@ -772,35 +744,36 @@
 
   // If the file fails to write, it is probably we are running out of disk space
   // and the file system doesn't support sparse file.
-  if (file.Write(kLargeFileOffset - kDataLen - 1, kData, kDataLen) < 0)
+  if (file.Write(kLargeFileOffset - kDataLen - 1, kData, kDataLen) < 0) {
     return;
+  }
 
   ASSERT_EQ(kDataLen, file.Write(kLargeFileOffset + 1, kData, kDataLen));
 }
 
 TEST(FileTest, AddFlagsForPassingToUntrustedProcess) {
   {
-    uint32_t flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
-    flags = base::File::AddFlagsForPassingToUntrustedProcess(flags);
-    EXPECT_EQ(flags, base::File::FLAG_OPEN | base::File::FLAG_READ);
+    uint32_t flags = File::FLAG_OPEN | File::FLAG_READ;
+    flags = File::AddFlagsForPassingToUntrustedProcess(flags);
+    EXPECT_EQ(flags, File::FLAG_OPEN | File::FLAG_READ);
   }
   {
-    uint32_t flags = base::File::FLAG_OPEN | base::File::FLAG_WRITE;
-    flags = base::File::AddFlagsForPassingToUntrustedProcess(flags);
-    EXPECT_EQ(flags, base::File::FLAG_OPEN | base::File::FLAG_WRITE |
-                         base::File::FLAG_WIN_NO_EXECUTE);
+    uint32_t flags = File::FLAG_OPEN | File::FLAG_WRITE;
+    flags = File::AddFlagsForPassingToUntrustedProcess(flags);
+    EXPECT_EQ(flags,
+              File::FLAG_OPEN | File::FLAG_WRITE | File::FLAG_WIN_NO_EXECUTE);
   }
 }
 
 #if BUILDFLAG(IS_WIN)
 TEST(FileTest, GetInfoForDirectory) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath empty_dir =
       temp_dir.GetPath().Append(FILE_PATH_LITERAL("gpfi_test"));
   ASSERT_TRUE(CreateDirectory(empty_dir));
 
-  base::File dir(
+  File dir(
       ::CreateFile(empty_dir.value().c_str(), GENERIC_READ | GENERIC_WRITE,
                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
                    OPEN_EXISTING,
@@ -808,7 +781,7 @@
                    NULL));
   ASSERT_TRUE(dir.IsValid());
 
-  base::File::Info info;
+  File::Info info;
   EXPECT_TRUE(dir.GetInfo(&info));
   EXPECT_TRUE(info.is_directory);
   EXPECT_FALSE(info.is_symbolic_link);
@@ -816,63 +789,59 @@
 }
 
 TEST(FileTest, DeleteNoop) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // Creating and closing a file with DELETE perms should do nothing special.
-  File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_CAN_DELETE_ON_CLOSE));
+  File file(file_path, (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+                        File::FLAG_CAN_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
   file.Close();
-  ASSERT_TRUE(base::PathExists(file_path));
+  ASSERT_TRUE(PathExists(file_path));
 }
 
 TEST(FileTest, Delete) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // Creating a file with DELETE and then marking for delete on close should
   // delete it.
-  File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_CAN_DELETE_ON_CLOSE));
+  File file(file_path, (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+                        File::FLAG_CAN_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
   ASSERT_TRUE(file.DeleteOnClose(true));
   file.Close();
-  ASSERT_FALSE(base::PathExists(file_path));
+  ASSERT_FALSE(PathExists(file_path));
 }
 
 TEST(FileTest, DeleteThenRevoke) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // Creating a file with DELETE, marking it for delete, then clearing delete on
   // close should not delete it.
-  File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_CAN_DELETE_ON_CLOSE));
+  File file(file_path, (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+                        File::FLAG_CAN_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
   ASSERT_TRUE(file.DeleteOnClose(true));
   ASSERT_TRUE(file.DeleteOnClose(false));
   file.Close();
-  ASSERT_TRUE(base::PathExists(file_path));
+  ASSERT_TRUE(PathExists(file_path));
 }
 
 TEST(FileTest, IrrevokableDeleteOnClose) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // DELETE_ON_CLOSE cannot be revoked by this opener.
   File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_DELETE_ON_CLOSE |
-             base::File::FLAG_WIN_SHARE_DELETE |
-             base::File::FLAG_CAN_DELETE_ON_CLOSE));
+            (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+             File::FLAG_DELETE_ON_CLOSE | File::FLAG_WIN_SHARE_DELETE |
+             File::FLAG_CAN_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
   // https://msdn.microsoft.com/library/windows/desktop/aa364221.aspx says that
   // setting the dispositon has no effect if the handle was opened with
@@ -881,84 +850,80 @@
   // to indicate success on Windows 10.)
   file.DeleteOnClose(false);
   file.Close();
-  ASSERT_FALSE(base::PathExists(file_path));
+  ASSERT_FALSE(PathExists(file_path));
 }
 
 TEST(FileTest, IrrevokableDeleteOnCloseOther) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // DELETE_ON_CLOSE cannot be revoked by another opener.
   File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_DELETE_ON_CLOSE |
-             base::File::FLAG_WIN_SHARE_DELETE |
-             base::File::FLAG_CAN_DELETE_ON_CLOSE));
+            (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+             File::FLAG_DELETE_ON_CLOSE | File::FLAG_WIN_SHARE_DELETE |
+             File::FLAG_CAN_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
 
   File file2(file_path,
-             (base::File::FLAG_OPEN | base::File::FLAG_READ |
-              base::File::FLAG_WRITE | base::File::FLAG_WIN_SHARE_DELETE |
-              base::File::FLAG_CAN_DELETE_ON_CLOSE));
+             (File::FLAG_OPEN | File::FLAG_READ | File::FLAG_WRITE |
+              File::FLAG_WIN_SHARE_DELETE | File::FLAG_CAN_DELETE_ON_CLOSE));
   ASSERT_TRUE(file2.IsValid());
 
   file2.DeleteOnClose(false);
   file2.Close();
-  ASSERT_TRUE(base::PathExists(file_path));
+  ASSERT_TRUE(PathExists(file_path));
   file.Close();
-  ASSERT_FALSE(base::PathExists(file_path));
+  ASSERT_FALSE(PathExists(file_path));
 }
 
 TEST(FileTest, DeleteWithoutPermission) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // It should not be possible to mark a file for deletion when it was not
   // created/opened with DELETE.
-  File file(file_path, (base::File::FLAG_CREATE | base::File::FLAG_READ |
-                        base::File::FLAG_WRITE));
+  File file(file_path,
+            (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE));
   ASSERT_TRUE(file.IsValid());
   ASSERT_FALSE(file.DeleteOnClose(true));
   file.Close();
-  ASSERT_TRUE(base::PathExists(file_path));
+  ASSERT_TRUE(PathExists(file_path));
 }
 
 TEST(FileTest, UnsharedDeleteOnClose) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // Opening with DELETE_ON_CLOSE when a previous opener hasn't enabled sharing
   // will fail.
-  File file(file_path, (base::File::FLAG_CREATE | base::File::FLAG_READ |
-                        base::File::FLAG_WRITE));
+  File file(file_path,
+            (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE));
   ASSERT_TRUE(file.IsValid());
-  File file2(
-      file_path,
-      (base::File::FLAG_OPEN | base::File::FLAG_READ | base::File::FLAG_WRITE |
-       base::File::FLAG_DELETE_ON_CLOSE | base::File::FLAG_WIN_SHARE_DELETE));
+  File file2(file_path,
+             (File::FLAG_OPEN | File::FLAG_READ | File::FLAG_WRITE |
+              File::FLAG_DELETE_ON_CLOSE | File::FLAG_WIN_SHARE_DELETE));
   ASSERT_FALSE(file2.IsValid());
 
   file.Close();
-  ASSERT_TRUE(base::PathExists(file_path));
+  ASSERT_TRUE(PathExists(file_path));
 }
 
 TEST(FileTest, NoDeleteOnCloseWithMappedFile) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
   // Mapping a file into memory blocks DeleteOnClose.
-  File file(file_path,
-            (base::File::FLAG_CREATE | base::File::FLAG_READ |
-             base::File::FLAG_WRITE | base::File::FLAG_CAN_DELETE_ON_CLOSE));
+  File file(file_path, (File::FLAG_CREATE | File::FLAG_READ | File::FLAG_WRITE |
+                        File::FLAG_CAN_DELETE_ON_CLOSE));
   ASSERT_TRUE(file.IsValid());
   ASSERT_EQ(5, file.WriteAtCurrentPos("12345", 5));
 
   {
-    base::MemoryMappedFile mapping;
+    MemoryMappedFile mapping;
     ASSERT_TRUE(mapping.Initialize(file.Duplicate()));
     ASSERT_EQ(5U, mapping.length());
 
@@ -966,17 +931,16 @@
   }
 
   file.Close();
-  ASSERT_TRUE(base::PathExists(file_path));
+  ASSERT_TRUE(PathExists(file_path));
 }
 
 // Check that we handle the async bit being set incorrectly in a sane way.
 TEST(FileTest, UseSyncApiWithAsyncFile) {
-  base::ScopedTempDir temp_dir;
+  ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
-  File file(file_path, base::File::FLAG_CREATE | base::File::FLAG_WRITE |
-                           base::File::FLAG_ASYNC);
+  File file(file_path, File::FLAG_CREATE | File::FLAG_WRITE | File::FLAG_ASYNC);
   File lying_file(file.TakePlatformFile(), false /* async */);
   ASSERT_TRUE(lying_file.IsValid());
 
@@ -989,7 +953,7 @@
         // When this test is running as Admin, TMP gets ignored and temporary
         // files/folders are created in %ProgramFiles%. This means that the
         // temporary folder created by the death test never gets deleted, as it
-        // crashes before the `base::ScopedTempDir` goes out of scope and also
+        // crashes before the `ScopedTempDir` goes out of scope and also
         // does not get automatically cleaned by by the test runner.
         //
         // To avoid this from happening, this death test explicitly creates the
@@ -997,16 +961,17 @@
         // process to a temporary folder for the test. This means that the
         // folder created here is always deleted during test runner cleanup.
         std::string tmp_folder;
-        ASSERT_TRUE(base::Environment::Create()->GetVar("TMP", &tmp_folder));
-        base::ScopedTempDir temp_dir;
+        ASSERT_TRUE(Environment::Create()->GetVar("TMP", &tmp_folder));
+        ScopedTempDir temp_dir;
         ASSERT_TRUE(temp_dir.CreateUniqueTempDirUnderPath(
-            base::FilePath(base::UTF8ToWide(tmp_folder))));
+            FilePath(UTF8ToWide(tmp_folder))));
         FilePath file_path = temp_dir.GetPath().AppendASCII("file");
 
-        File file(file_path,
-                  base::File::FLAG_CREATE | base::File::FLAG_WIN_EXECUTE |
-                      base::File::FLAG_READ | base::File::FLAG_WIN_NO_EXECUTE);
+        File file(file_path, File::FLAG_CREATE | File::FLAG_WIN_EXECUTE |
+                                 File::FLAG_READ | File::FLAG_WIN_NO_EXECUTE);
       },
       "FLAG_WIN_NO_EXECUTE");
 }
 #endif  // BUILDFLAG(IS_WIN)
+
+}  // namespace base
diff --git a/base/files/file_util.cc b/base/files/file_util.cc
index f85fda2..6211201 100644
--- a/base/files/file_util.cc
+++ b/base/files/file_util.cc
@@ -331,7 +331,7 @@
   bool read_successs = ReadStreamToSpanWithMaxSize(
       stream, max_size, [&content_string](size_t size) {
         content_string.resize(size);
-        return as_writable_bytes(make_span(content_string));
+        return as_writable_byte_span(content_string);
       });
 
   if (contents) {
@@ -355,7 +355,7 @@
                                    std::numeric_limits<size_t>::max(),
                                    [&bytes](size_t size) {
                                      bytes.resize(size);
-                                     return make_span(bytes);
+                                     return span(bytes);
                                    })) {
     return std::nullopt;
   }
@@ -486,7 +486,7 @@
     return -1;
   }
   std::optional<uint64_t> result =
-      ReadFile(filename, make_span(data, static_cast<uint32_t>(max_size)));
+      ReadFile(filename, span(data, static_cast<uint32_t>(max_size)));
   if (!result) {
     return -1;
   }
@@ -494,7 +494,7 @@
 }
 
 bool WriteFile(const FilePath& filename, std::string_view data) {
-  return WriteFile(filename, as_bytes(make_span(data)));
+  return WriteFile(filename, as_byte_span(data));
 }
 
 FilePath GetUniquePath(const FilePath& path) {
diff --git a/base/files/file_util_posix.cc b/base/files/file_util_posix.cc
index 25b37054..c1f484b 100644
--- a/base/files/file_util_posix.cc
+++ b/base/files/file_util_posix.cc
@@ -1101,7 +1101,7 @@
 }
 
 bool WriteFileDescriptor(int fd, std::string_view data) {
-  return WriteFileDescriptor(fd, as_bytes(make_span(data)));
+  return WriteFileDescriptor(fd, as_byte_span(data));
 }
 
 bool AllocateFileRegion(File* file, int64_t offset, size_t size) {
@@ -1210,7 +1210,7 @@
 }
 
 bool AppendToFile(const FilePath& filename, std::string_view data) {
-  return AppendToFile(filename, as_bytes(make_span(data)));
+  return AppendToFile(filename, as_byte_span(data));
 }
 
 bool GetCurrentDirectory(FilePath* dir) {
diff --git a/base/files/file_util_win.cc b/base/files/file_util_win.cc
index ec523fd40..f93a90c 100644
--- a/base/files/file_util_win.cc
+++ b/base/files/file_util_win.cc
@@ -1034,7 +1034,7 @@
 }
 
 bool AppendToFile(const FilePath& filename, std::string_view data) {
-  return AppendToFile(filename, as_bytes(make_span(data)));
+  return AppendToFile(filename, as_byte_span(data));
 }
 
 bool GetCurrentDirectory(FilePath* dir) {
diff --git a/base/hash/hash.cc b/base/hash/hash.cc
index 6c75a3f..9a23491 100644
--- a/base/hash/hash.cc
+++ b/base/hash/hash.cc
@@ -148,7 +148,7 @@
 }
 
 uint32_t PersistentHash(std::string_view str) {
-  return PersistentHash(as_bytes(make_span(str)));
+  return PersistentHash(as_byte_span(str));
 }
 
 size_t HashInts32(uint32_t value1, uint32_t value2) {
diff --git a/base/hash/hash.h b/base/hash/hash.h
index 335bc3d7..3464d61e 100644
--- a/base/hash/hash.h
+++ b/base/hash/hash.h
@@ -35,7 +35,7 @@
 // May changed without warning, do not expect stability of outputs.
 BASE_EXPORT size_t FastHash(base::span<const uint8_t> data);
 inline size_t FastHash(std::string_view str) {
-  return FastHash(as_bytes(make_span(str)));
+  return FastHash(as_byte_span(str));
 }
 
 // Computes a hash of a memory buffer. This hash function must not change so
diff --git a/base/hash/legacy_hash_unittest.cc b/base/hash/legacy_hash_unittest.cc
index 8b6d76f..353a6c4 100644
--- a/base/hash/legacy_hash_unittest.cc
+++ b/base/hash/legacy_hash_unittest.cc
@@ -26,13 +26,12 @@
   };
   for (const auto& test_case : kTestCases) {
     SCOPED_TRACE(test_case.input);
-    auto bytes = as_bytes(make_span(test_case.input));
-    EXPECT_EQ(test_case.output, CityHash64(bytes));
+    EXPECT_EQ(test_case.output, CityHash64(as_byte_span(test_case.input)));
   }
   for (const auto& test_case : kTestCases) {
     SCOPED_TRACE(test_case.input);
-    auto bytes = as_bytes(make_span(test_case.input));
-    EXPECT_EQ(test_case.output_with_seed, CityHash64WithSeed(bytes, 112358));
+    EXPECT_EQ(test_case.output_with_seed,
+              CityHash64WithSeed(as_byte_span(test_case.input), 112358));
   }
 }
 
diff --git a/base/i18n/streaming_utf8_validator_unittest.cc b/base/i18n/streaming_utf8_validator_unittest.cc
index 0398b02..a6dafec 100644
--- a/base/i18n/streaming_utf8_validator_unittest.cc
+++ b/base/i18n/streaming_utf8_validator_unittest.cc
@@ -282,28 +282,24 @@
 // test.
 TEST(StreamingUtf8ValidatorTest, NulIsValid) {
   static const char kNul[] = "\x00";
-  EXPECT_EQ(VALID_ENDPOINT, StreamingUtf8Validator().AddBytes(
-                                base::as_bytes(base::make_span(kNul, 1u))));
+  EXPECT_EQ(VALID_ENDPOINT,
+            StreamingUtf8Validator().AddBytes(byte_span_from_cstring(kNul)));
 }
 
 // Just a basic sanity test before we start getting fancy.
 TEST(StreamingUtf8ValidatorTest, HelloWorld) {
   static const char kHelloWorld[] = "Hello, World!";
-  EXPECT_EQ(VALID_ENDPOINT,
-            StreamingUtf8Validator().AddBytes(base::as_bytes(
-                base::make_span(kHelloWorld, strlen(kHelloWorld)))));
+  EXPECT_EQ(VALID_ENDPOINT, StreamingUtf8Validator().AddBytes(
+                                byte_span_from_cstring(kHelloWorld)));
 }
 
 // Check that the Reset() method works.
 TEST(StreamingUtf8ValidatorTest, ResetWorks) {
   StreamingUtf8Validator validator;
-  EXPECT_EQ(INVALID,
-            validator.AddBytes(base::as_bytes(base::make_span("\xC0", 1u))));
-  EXPECT_EQ(INVALID,
-            validator.AddBytes(base::as_bytes(base::make_span("a", 1u))));
+  EXPECT_EQ(INVALID, validator.AddBytes(byte_span_from_cstring("\xC0")));
+  EXPECT_EQ(INVALID, validator.AddBytes(byte_span_from_cstring("a")));
   validator.Reset();
-  EXPECT_EQ(VALID_ENDPOINT,
-            validator.AddBytes(base::as_bytes(base::make_span("a", 1u))));
+  EXPECT_EQ(VALID_ENDPOINT, validator.AddBytes(byte_span_from_cstring("a")));
 }
 
 TEST_F(StreamingUtf8ValidatorSingleSequenceTest, Valid) {
diff --git a/base/immediate_crash_unittest.cc b/base/immediate_crash_unittest.cc
index a3dbc802..2fe57bc 100644
--- a/base/immediate_crash_unittest.cc
+++ b/base/immediate_crash_unittest.cc
@@ -150,8 +150,9 @@
   const Instruction* const start = static_cast<Instruction*>(std::min(a, b));
   const Instruction* const end = static_cast<Instruction*>(std::max(a, b));
 
-  for (const Instruction& instruction : make_span(start, end))
+  for (const Instruction& instruction : span(start, end)) {
     body->push_back(instruction);
+  }
 }
 
 #if defined(OFFICIAL_BUILD)
@@ -207,7 +208,7 @@
   // code will falsely exit early, having not found the real expected crash
   // sequence, so this may not adequately ensure that the immediate crash
   // sequence is present. We do check when not under coverage, at least.
-  return DropUntilMatch(instructions, base::make_span(kRequiredBody));
+  return DropUntilMatch(instructions, span(kRequiredBody));
 #else
   return instructions;
 #endif  // USE_CLANG_COVERAGE || BUILDFLAG(CLANG_PROFILING)
diff --git a/base/json/json_writer_unittest.cc b/base/json/json_writer_unittest.cc
index 6e1c1ae..e24ed3c 100644
--- a/base/json/json_writer_unittest.cc
+++ b/base/json/json_writer_unittest.cc
@@ -107,7 +107,7 @@
 }
 
 TEST(JsonWriterTest, BinaryValues) {
-  const auto kBinaryData = base::as_bytes(base::make_span("asdf", 4u));
+  const auto kBinaryData = byte_span_from_cstring("asdf");
 
   // Binary values should return errors unless suppressed via the
   // `OPTIONS_OMIT_BINARY_VALUES` flag.
diff --git a/base/memory/platform_shared_memory_mapper_android.cc b/base/memory/platform_shared_memory_mapper_android.cc
index c1cf53e..4bde5375 100644
--- a/base/memory/platform_shared_memory_mapper_android.cc
+++ b/base/memory/platform_shared_memory_mapper_android.cc
@@ -33,7 +33,7 @@
     return std::nullopt;
   }
 
-  return make_span(static_cast<uint8_t*>(address), size);
+  return span(static_cast<uint8_t*>(address), size);
 }
 
 void PlatformSharedMemoryMapper::Unmap(span<uint8_t> mapping) {
diff --git a/base/memory/platform_shared_memory_mapper_fuchsia.cc b/base/memory/platform_shared_memory_mapper_fuchsia.cc
index db6bd7c..64b3ce2 100644
--- a/base/memory/platform_shared_memory_mapper_fuchsia.cc
+++ b/base/memory/platform_shared_memory_mapper_fuchsia.cc
@@ -32,7 +32,7 @@
     return std::nullopt;
   }
 
-  return make_span(reinterpret_cast<uint8_t*>(addr), size);
+  return span(reinterpret_cast<uint8_t*>(addr), size);
 }
 
 void PlatformSharedMemoryMapper::Unmap(span<uint8_t> mapping) {
diff --git a/base/memory/platform_shared_memory_mapper_posix.cc b/base/memory/platform_shared_memory_mapper_posix.cc
index 192f5d17..5bb3fb4 100644
--- a/base/memory/platform_shared_memory_mapper_posix.cc
+++ b/base/memory/platform_shared_memory_mapper_posix.cc
@@ -30,7 +30,7 @@
     return std::nullopt;
   }
 
-  return make_span(static_cast<uint8_t*>(address), size);
+  return span(static_cast<uint8_t*>(address), size);
 }
 
 void PlatformSharedMemoryMapper::Unmap(span<uint8_t> mapping) {
diff --git a/base/memory/platform_shared_memory_mapper_win.cc b/base/memory/platform_shared_memory_mapper_win.cc
index eef28ad..3904974e 100644
--- a/base/memory/platform_shared_memory_mapper_win.cc
+++ b/base/memory/platform_shared_memory_mapper_win.cc
@@ -49,8 +49,7 @@
     return std::nullopt;
   }
 
-  return make_span(static_cast<uint8_t*>(address),
-                   GetMemorySectionSize(address));
+  return span(static_cast<uint8_t*>(address), GetMemorySectionSize(address));
 }
 
 void PlatformSharedMemoryMapper::Unmap(span<uint8_t> mapping) {
diff --git a/base/memory/shared_memory_mapping.cc b/base/memory/shared_memory_mapping.cc
index 53938f46..edf8123 100644
--- a/base/memory/shared_memory_mapping.cc
+++ b/base/memory/shared_memory_mapping.cc
@@ -73,8 +73,7 @@
   size_t adjusted_size =
       mapped_span_.size() +
       static_cast<size_t>(mapped_span_.data() - aligned_data);
-  span<uint8_t> span_to_unmap = make_span(aligned_data, adjusted_size);
-  mapper->Unmap(span_to_unmap);
+  mapper->Unmap(span(aligned_data, adjusted_size));
 }
 
 ReadOnlySharedMemoryMapping::ReadOnlySharedMemoryMapping() = default;
diff --git a/base/metrics/persistent_histogram_allocator.cc b/base/metrics/persistent_histogram_allocator.cc
index d6cf8c6..825c117 100644
--- a/base/metrics/persistent_histogram_allocator.cc
+++ b/base/metrics/persistent_histogram_allocator.cc
@@ -225,8 +225,8 @@
   // |sample_map_records|, up until |until_value| (if applicable).
   std::vector<PersistentMemoryAllocator::Reference> new_references;
   CHECK_GE(found_records.size(), sample_map_records->seen_);
-  auto new_found_records = base::make_span(found_records)
-                               .subspan(/*offset=*/sample_map_records->seen_);
+  auto new_found_records =
+      span(found_records).subspan(/*offset=*/sample_map_records->seen_);
   new_references.reserve(new_found_records.size());
   for (const auto& new_record : new_found_records) {
     new_references.push_back(new_record.reference);
diff --git a/base/metrics/persistent_memory_allocator.cc b/base/metrics/persistent_memory_allocator.cc
index 9e5f585..269df891 100644
--- a/base/metrics/persistent_memory_allocator.cc
+++ b/base/metrics/persistent_memory_allocator.cc
@@ -1317,7 +1317,7 @@
     DUMP_WILL_BE_NOTREACHED();
     return span<uint8_t>();
   }
-  return make_span(mem + offset_, size_ - offset_);
+  return span(mem + offset_, size_ - offset_);
 }
 
 }  // namespace base
diff --git a/base/metrics/persistent_memory_allocator.h b/base/metrics/persistent_memory_allocator.h
index 3ab70be..0265d26f 100644
--- a/base/metrics/persistent_memory_allocator.h
+++ b/base/metrics/persistent_memory_allocator.h
@@ -946,8 +946,8 @@
     // will result.
     CHECK_EQ(offset_ % alignof(T), 0u);
     span<uint8_t> untyped = GetUntyped();
-    return make_span(reinterpret_cast<T*>(untyped.data()),
-                     untyped.size() / sizeof(T));
+    return span(reinterpret_cast<T*>(untyped.data()),
+                untyped.size() / sizeof(T));
   }
 
   // Gets the internal reference value. If this returns a non-zero value then
diff --git a/base/metrics/sample_vector.h b/base/metrics/sample_vector.h
index 03e3bacb..c92c965 100644
--- a/base/metrics/sample_vector.h
+++ b/base/metrics/sample_vector.h
@@ -102,7 +102,7 @@
     if (data == nullptr) {
       return std::nullopt;
     }
-    return std::make_optional(make_span(data, counts_size_));
+    return span(data, counts_size_);
   }
 
   std::optional<span<const HistogramBase::AtomicCount>> counts() const {
@@ -111,7 +111,7 @@
     if (data == nullptr) {
       return std::nullopt;
     }
-    return std::make_optional(make_span(data, counts_size_));
+    return span(data, counts_size_);
   }
 
   void set_counts(span<HistogramBase::AtomicCount> counts) const {
diff --git a/base/pickle.cc b/base/pickle.cc
index c2755cb..d5031bc 100644
--- a/base/pickle.cc
+++ b/base/pickle.cc
@@ -213,14 +213,14 @@
   return ReadBytes(data, *length);
 }
 
-std::optional<base::span<const uint8_t>> PickleIterator::ReadData() {
+std::optional<span<const uint8_t>> PickleIterator::ReadData() {
   const char* ptr;
   size_t length;
 
   if (!ReadData(&ptr, &length))
     return std::nullopt;
 
-  return base::as_bytes(base::make_span(ptr, length));
+  return as_bytes(span(ptr, length));
 }
 
 bool PickleIterator::ReadBytes(const char** data, size_t length) {
@@ -357,7 +357,7 @@
 }
 
 void Pickle::WriteBytes(const void* data, size_t length) {
-  WriteBytesCommon(make_span(static_cast<const uint8_t*>(data), length));
+  WriteBytesCommon(span(static_cast<const uint8_t*>(data), length));
 }
 
 void Pickle::WriteBytes(span<const uint8_t> data) {
@@ -449,7 +449,7 @@
 
 template <size_t length>
 void Pickle::WriteBytesStatic(const void* data) {
-  WriteBytesCommon(make_span(static_cast<const uint8_t*>(data), length));
+  WriteBytesCommon(span(static_cast<const uint8_t*>(data), length));
 }
 
 template void Pickle::WriteBytesStatic<2>(const void* data);
diff --git a/base/pickle.h b/base/pickle.h
index fe98ce67..69a894d 100644
--- a/base/pickle.h
+++ b/base/pickle.h
@@ -306,7 +306,7 @@
   }
 
   span<const uint8_t> payload_bytes() const {
-    return as_bytes(make_span(payload(), payload_size()));
+    return as_bytes(span(payload(), payload_size()));
   }
 
  protected:
diff --git a/base/profiler/chrome_unwind_info_android_unittest.cc b/base/profiler/chrome_unwind_info_android_unittest.cc
index 2785925..39ede40 100644
--- a/base/profiler/chrome_unwind_info_android_unittest.cc
+++ b/base/profiler/chrome_unwind_info_android_unittest.cc
@@ -86,13 +86,13 @@
   ASSERT_EQ(&data[256], reinterpret_cast<const uint8_t*>(
                             &unwind_info.unwind_instruction_table[0]));
 
-  ExpectSpanSizeAndContentsEqual(unwind_info.page_table, make_span(page_table));
+  ExpectSpanSizeAndContentsEqual(unwind_info.page_table, span(page_table));
   ExpectSpanSizeAndContentsEqual(unwind_info.function_table,
-                                 make_span(function_table));
+                                 span(function_table));
   ExpectSpanSizeAndContentsEqual(unwind_info.function_offset_table,
-                                 make_span(function_offset_table));
+                                 span(function_offset_table));
   ExpectSpanSizeAndContentsEqual(unwind_info.unwind_instruction_table,
-                                 make_span(unwind_instruction_table));
+                                 span(unwind_instruction_table));
 }
 
 }  // namespace base
diff --git a/base/strings/strcat.h b/base/strings/strcat.h
index b2a76568..8997593 100644
--- a/base/strings/strcat.h
+++ b/base/strings/strcat.h
@@ -68,12 +68,12 @@
 
 // Initializer list forwards to the array version.
 inline std::string StrCat(std::initializer_list<std::string_view> pieces) {
-  return StrCat(make_span(pieces));
+  return StrCat(span(pieces));
 }
 
 inline std::u16string StrCat(
     std::initializer_list<std::u16string_view> pieces) {
-  return StrCat(make_span(pieces));
+  return StrCat(span(pieces));
 }
 
 // StrAppend -------------------------------------------------------------------
@@ -95,12 +95,12 @@
 // Initializer list forwards to the array version.
 inline void StrAppend(std::string* dest,
                       std::initializer_list<std::string_view> pieces) {
-  StrAppend(dest, make_span(pieces));
+  StrAppend(dest, span(pieces));
 }
 
 inline void StrAppend(std::u16string* dest,
                       std::initializer_list<std::u16string_view> pieces) {
-  StrAppend(dest, make_span(pieces));
+  StrAppend(dest, span(pieces));
 }
 
 }  // namespace base
diff --git a/base/strings/strcat_win.h b/base/strings/strcat_win.h
index e230373f..9bd7007 100644
--- a/base/strings/strcat_win.h
+++ b/base/strings/strcat_win.h
@@ -22,7 +22,7 @@
 
 inline void StrAppend(std::wstring* dest,
                       std::initializer_list<std::wstring_view> pieces) {
-  StrAppend(dest, make_span(pieces));
+  StrAppend(dest, span(pieces));
 }
 
 [[nodiscard]] BASE_EXPORT std::wstring StrCat(
@@ -30,7 +30,7 @@
 [[nodiscard]] BASE_EXPORT std::wstring StrCat(span<const std::wstring> pieces);
 
 inline std::wstring StrCat(std::initializer_list<std::wstring_view> pieces) {
-  return StrCat(make_span(pieces));
+  return StrCat(span(pieces));
 }
 
 }  // namespace base
diff --git a/base/test/launcher/unit_test_launcher.cc b/base/test/launcher/unit_test_launcher.cc
index 203faa9..79bcac6c 100644
--- a/base/test/launcher/unit_test_launcher.cc
+++ b/base/test/launcher/unit_test_launcher.cc
@@ -284,8 +284,7 @@
   // Fuzztest requires a narrow command-line.
   CHECK(*argc >= 0);
   const auto argc_s = static_cast<size_t>(*argc);
-  base::span<wchar_t*> wide_command_line =
-      UNSAFE_BUFFERS(base::make_span(argv, argc_s));
+  span<wchar_t*> wide_command_line = UNSAFE_BUFFERS(span(argv, argc_s));
   std::vector<std::string> narrow_command_line;
   std::vector<char*> narrow_command_line_pointers;
   narrow_command_line.reserve(argc_s);
diff --git a/base/token.h b/base/token.h
index d90ceeb..e52c9747 100644
--- a/base/token.h
+++ b/base/token.h
@@ -48,9 +48,7 @@
 
   constexpr bool is_zero() const { return words_[0] == 0 && words_[1] == 0; }
 
-  span<const uint8_t, 16> AsBytes() const {
-    return as_bytes(make_span(words_));
-  }
+  span<const uint8_t, 16> AsBytes() const { return as_byte_span(words_); }
 
   friend constexpr auto operator<=>(const Token& lhs,
                                     const Token& rhs) = default;
diff --git a/base/trace_event/category_registry.cc b/base/trace_event/category_registry.cc
index d094dfb..0ac653e 100644
--- a/base/trace_event/category_registry.cc
+++ b/base/trace_event/category_registry.cc
@@ -134,12 +134,12 @@
 }
 
 // static
-base::span<TraceCategory> CategoryRegistry::GetAllCategories() {
+span<TraceCategory> CategoryRegistry::GetAllCategories() {
   // The |categories_| array is append only. We have to only guarantee to
   // not return an index to a category which is being initialized by
   // GetOrCreateCategoryByName().
   size_t category_index = category_index_.load(std::memory_order_acquire);
-  return base::make_span(categories_).first(category_index);
+  return span(categories_).first(category_index);
 }
 
 // static
diff --git a/base/trace_event/cfi_backtrace_android_unittest.cc b/base/trace_event/cfi_backtrace_android_unittest.cc
index 9427078..d40f6ac6 100644
--- a/base/trace_event/cfi_backtrace_android_unittest.cc
+++ b/base/trace_event/cfi_backtrace_android_unittest.cc
@@ -88,7 +88,7 @@
                       0xdc, 0x40, 0x1, 0x4, 0x2e};
   FilePath temp_path;
   CreateTemporaryFile(&temp_path);
-  EXPECT_TRUE(WriteFile(temp_path, base::as_bytes(base::make_span(input))));
+  EXPECT_TRUE(WriteFile(temp_path, as_byte_span(input)));
 
   unwinder->cfi_mmap_.reset(new MemoryMappedFile());
   ASSERT_TRUE(unwinder->cfi_mmap_->Initialize(temp_path));
diff --git a/base/trace_event/heap_profiler_allocation_context.cc b/base/trace_event/heap_profiler_allocation_context.cc
index 9c38bbe..ed4d619f 100644
--- a/base/trace_event/heap_profiler_allocation_context.cc
+++ b/base/trace_event/heap_profiler_allocation_context.cc
@@ -73,8 +73,8 @@
   for (size_t i = 0; i != backtrace.frame_count; ++i) {
     values[i] = backtrace.frames[i].value;
   }
-  auto values_span = base::make_span(values).first(backtrace.frame_count);
-  return base::PersistentHash(base::as_bytes(values_span));
+  return base::PersistentHash(
+      base::as_bytes(base::span(values).first(backtrace.frame_count)));
 }
 
 size_t hash<AllocationContext>::operator()(const AllocationContext& ctx) const {
diff --git a/base/uuid_unittest.cc b/base/uuid_unittest.cc
index f7e44820e8..d9b04ca 100644
--- a/base/uuid_unittest.cc
+++ b/base/uuid_unittest.cc
@@ -198,13 +198,11 @@
                                         0xfffffffffffffffcull};
 
   const Uuid guid1a =
-      Uuid::FormatRandomDataAsV4ForTesting(as_bytes(make_span(bytes1a)));
+      Uuid::FormatRandomDataAsV4ForTesting(as_byte_span(bytes1a));
   const Uuid guid1b =
-      Uuid::FormatRandomDataAsV4ForTesting(as_bytes(make_span(bytes1b)));
-  const Uuid guid2 =
-      Uuid::FormatRandomDataAsV4ForTesting(as_bytes(make_span(bytes2)));
-  const Uuid guid3 =
-      Uuid::FormatRandomDataAsV4ForTesting(as_bytes(make_span(bytes3)));
+      Uuid::FormatRandomDataAsV4ForTesting(as_byte_span(bytes1b));
+  const Uuid guid2 = Uuid::FormatRandomDataAsV4ForTesting(as_byte_span(bytes2));
+  const Uuid guid3 = Uuid::FormatRandomDataAsV4ForTesting(as_byte_span(bytes3));
 
   EXPECT_TRUE(guid1a.is_valid());
   EXPECT_TRUE(guid1b.is_valid());
diff --git a/base/win/access_token.cc b/base/win/access_token.cc
index bf5482a9..d9564cf 100644
--- a/base/win/access_token.cc
+++ b/base/win/access_token.cc
@@ -630,9 +630,8 @@
     return false;
   }
 
-  for (auto privileges = base::make_span(&token_privileges->Privileges[0],
-                                         token_privileges->PrivilegeCount);
-       auto& privilege : privileges) {
+  for (auto& privilege : span(&token_privileges->Privileges[0],
+                              token_privileges->PrivilegeCount)) {
     privilege.Attributes = SE_PRIVILEGE_REMOVED;
   }
   return ::AdjustTokenPrivileges(
diff --git a/base/win/pe_image_reader.cc b/base/win/pe_image_reader.cc
index 85a5456e..8386735 100644
--- a/base/win/pe_image_reader.cc
+++ b/base/win/pe_image_reader.cc
@@ -107,7 +107,7 @@
 }
 
 span<const uint8_t> PeImageReader::GetOptionalHeaderData() {
-  return make_span(GetOptionalHeaderStart(), GetOptionalHeaderSize());
+  return span(GetOptionalHeaderStart(), GetOptionalHeaderSize());
 }
 
 size_t PeImageReader::GetNumberOfSections() {
@@ -155,7 +155,7 @@
           debug_directory_data[index * sizeof(IMAGE_DEBUG_DIRECTORY)]);
   const uint8_t* debug_data = nullptr;
   if (GetStructureAt(entry.PointerToRawData, entry.SizeOfData, &debug_data)) {
-    raw_data = make_span(debug_data, entry.SizeOfData);
+    raw_data = span(debug_data, entry.SizeOfData);
   }
   return &entry;
 }