Update from https://crrev.com/316786

cc/resources/bitmap_tile_task_worker_pool.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCES_BITMAP_TILE_TASK_WORKER_POOL_H_
 #define CC_RESOURCES_BITMAP_TILE_TASK_WORKER_POOL_H_
 
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
 #include "cc/resources/tile_task_runner.h"
 #include "cc/resources/tile_task_worker_pool.h"
 
 namespace base {
 namespace trace_event {
 class ConvertableToTraceFormat;
 }
-
-// TODO(ssid): remove these aliases after the tracing clients are moved to the
-// new trace_event namespace. See crbug.com/451032. ETA: March 2015
-namespace debug {
-using ::base::trace_event::ConvertableToTraceFormat;
 }
-}  // namespace base
 
 namespace cc {
 class ResourceProvider;
 
 class CC_EXPORT BitmapTileTaskWorkerPool : public TileTaskWorkerPool,
                                            public TileTaskRunner,
                                            public TileTaskClient {
  public:
   ~BitmapTileTaskWorkerPool() override;
 
@@ skipping 17 matching lines @@
       const Resource* resource) override;
   void ReleaseBufferForRaster(scoped_ptr<RasterBuffer> buffer) override;
 
  protected:
   BitmapTileTaskWorkerPool(base::SequencedTaskRunner* task_runner,
                            TaskGraphRunner* task_graph_runner,
                            ResourceProvider* resource_provider);
 
  private:
   void OnTaskSetFinished(TaskSet task_set);
-  scoped_refptr<base::debug::ConvertableToTraceFormat> StateAsValue() const;
+  scoped_refptr<base::trace_event::ConvertableToTraceFormat> StateAsValue()
+      const;
 
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   TaskGraphRunner* task_graph_runner_;
   const NamespaceToken namespace_token_;
   TileTaskRunnerClient* client_;
   ResourceProvider* resource_provider_;
 
   TaskSetCollection tasks_pending_;
 
   scoped_refptr<TileTask> task_set_finished_tasks_[kNumberOfTaskSets];
 
   // Task graph used when scheduling tasks and vector used to gather
   // completed tasks.
   TaskGraph graph_;
   Task::Vector completed_tasks_;
 
   base::WeakPtrFactory<BitmapTileTaskWorkerPool>
       task_set_finished_weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BitmapTileTaskWorkerPool);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_BITMAP_TILE_TASK_WORKER_POOL_H_