Replace URLDataSource::MessageLoopForRequestPath() with TaskRunnerForRequestPath().

content/public/browser/url_data_source.h

Index: content/public/browser/url_data_source.h
diff --git a/content/public/browser/url_data_source.h b/content/public/browser/url_data_source.h
index ed6a343845f8cad82effbf4c52d54cfba2778536..fc2814abfa745b7166dfd7da55789566aef3e8f4 100644
--- a/content/public/browser/url_data_source.h
+++ b/content/public/browser/url_data_source.h
@@ -9,11 +9,11 @@
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/resource_request_info.h"
 
 namespace base {
-class MessageLoop;
 class RefCountedMemory;
 }
 
@@ -68,15 +68,15 @@ class CONTENT_EXPORT URLDataSource {
 
   // The following methods are all called on the IO thread.
 
-  // Returns the MessageLoop on which the delegate wishes to have
+  // Returns the TaskRunner on which the delegate wishes to have
   // StartDataRequest called to handle the request for |path|. The default
   // implementation returns BrowserThread::UI. If the delegate does not care
   // which thread StartDataRequest is called on, this should return nullptr.
   // It may be beneficial to return nullptr for requests that are safe to handle
   // directly on the IO thread.  This can improve performance by satisfying such
   // requests more rapidly when there is a large amount of UI thread contention.
-  // Or the delegate can return a specific thread's Messageloop if they wish.
-  virtual base::MessageLoop* MessageLoopForRequestPath(
+  // Or the delegate can return a specific thread's TaskRunner if they wish.
+  virtual scoped_refptr<base::SingleThreadTaskRunner> TaskRunnerForRequestPath(
       const std::string& path) const;
 
   // Returns true if the URLDataSource should replace an existing URLDataSource