Migrate //chrome/browser/ash/fileapi to namespace ash

This CL is part of the Chrome OS source code directory migration:
https://docs.google.com/document/d/1g-98HpzA8XcoGBWUv1gQNr4rbnD5yfvbtYZyPDDbkaE.

Change-Id: I494f310a09c74a4516f9e2219c403cfb6f16786b
Bug: 1164001
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4011620
Reviewed-by: James Cook <[email protected]>
Owners-Override: James Cook <[email protected]>
Commit-Queue: Yeunjoo Choi <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1069550}
diff --git a/chrome/browser/platform_util_unittest.cc b/chrome/browser/platform_util_unittest.cc
index 42e5ce5..ac28f24 100644
--- a/chrome/browser/platform_util_unittest.cc
+++ b/chrome/browser/platform_util_unittest.cc
@@ -62,17 +62,16 @@
         browser_context->GetMountPoints();
 
     // New FileSystemBackend that uses our MockSpecialStoragePolicy.
-    additional_backends->push_back(
-        std::make_unique<chromeos::FileSystemBackend>(
-            nullptr,  // profile
-            nullptr,  // file_system_provider_delegate
-            nullptr,  // mtp_delegate
-            nullptr,  // arc_content_delegate
-            nullptr,  // arc_documents_provider_delegate
-            nullptr,  // drivefs_delegate
-            nullptr,  // smbfs_delegate
-            external_mount_points,
-            storage::ExternalMountPoints::GetSystemInstance()));
+    additional_backends->push_back(std::make_unique<ash::FileSystemBackend>(
+        nullptr,  // profile
+        nullptr,  // file_system_provider_delegate
+        nullptr,  // mtp_delegate
+        nullptr,  // arc_content_delegate
+        nullptr,  // arc_documents_provider_delegate
+        nullptr,  // drivefs_delegate
+        nullptr,  // smbfs_delegate
+        external_mount_points,
+        storage::ExternalMountPoints::GetSystemInstance()));
   }
 };