Convert Callbacks to OnceCallbacks in content shell APIs.

Also some MessageLoopRunner conversions to RunLoop since PRESUBMIT
demands it.

[email protected]

Bug: 953861
Change-Id: Ic5c05a655675cbbc94b32c16b3126a9ed5364792
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1590516
Reviewed-by: Avi Drissman <[email protected]>
Commit-Queue: danakj <[email protected]>
Cr-Commit-Position: refs/heads/master@{#655693}
diff --git a/content/shell/browser/shell_download_manager_delegate.h b/content/shell/browser/shell_download_manager_delegate.h
index 6086da5..3e4922d 100644
--- a/content/shell/browser/shell_download_manager_delegate.h
+++ b/content/shell/browser/shell_download_manager_delegate.h
@@ -38,15 +38,15 @@
  private:
   friend class base::RefCountedThreadSafe<ShellDownloadManagerDelegate>;
 
-  typedef base::Callback<void(const base::FilePath&)>
-      FilenameDeterminedCallback;
+  using FilenameDeterminedCallback =
+      base::OnceCallback<void(const base::FilePath&)>;
 
   static void GenerateFilename(const GURL& url,
                                const std::string& content_disposition,
                                const std::string& suggested_filename,
                                const std::string& mime_type,
                                const base::FilePath& suggested_directory,
-                               const FilenameDeterminedCallback& callback);
+                               FilenameDeterminedCallback callback);
   void OnDownloadPathGenerated(uint32_t download_id,
                                const DownloadTargetCallback& callback,
                                const base::FilePath& suggested_path);