Deprecate WebThread::getWebTaskRunner.

third_party/WebKit/public/platform/WebThread.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 47 matching lines @@
     virtual void run(double deadlineSeconds) = 0;
   };
 
   class BLINK_PLATFORM_EXPORT TaskObserver {
    public:
     virtual ~TaskObserver() {}
     virtual void willProcessTask() = 0;
     virtual void didProcessTask() = 0;
   };
 
-  // Returns a WebTaskRunner bound to the underlying scheduler's default task
-  // queue.
+  // DEPRECATED: Returns a WebTaskRunner bound to the underlying scheduler's
+  // default task queue.
+  //
+  // Default scheduler task queue does not give scheduler enough freedom to
+  // manage task priorities and should not be used.
+  // Use TaskRunnerHelper::get instead (crbug.com/624696).
   virtual WebTaskRunner* getWebTaskRunner() { return nullptr; }
   base::SingleThreadTaskRunner* getSingleThreadTaskRunner();
 
   virtual bool isCurrentThread() const = 0;
   virtual PlatformThreadId threadId() const { return 0; }
 
   // TaskObserver is an object that receives task notifications from the
   // MessageLoop
   // NOTE: TaskObserver implementation should be extremely fast!
   // This API is performance sensitive. Use only if you have a compelling
@@ skipping 11 matching lines @@
 
   // Returns the scheduler associated with the thread.
   virtual WebScheduler* scheduler() const = 0;
 
   virtual ~WebThread() {}
 };
 
 }  // namespace blink
 
 #endif