cc: Add traces for identification of raster buffer.

cc/raster/one_copy_raster_buffer_provider.cc

 // 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.
 
 #include "cc/raster/one_copy_raster_buffer_provider.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 28 matching lines @@
   ~RasterBufferImpl() override {}
 
   // Overridden from RasterBuffer:
   void Playback(
       const RasterSource* raster_source,
       const gfx::Rect& raster_full_rect,
       const gfx::Rect& raster_dirty_rect,
       uint64_t new_content_id,
       float scale,
       const RasterSource::PlaybackSettings& playback_settings) override {
+    TRACE_EVENT0("cc", "OneCopyRasterBuffer::Playback");
     worker_pool_->PlaybackAndCopyOnWorkerThread(
         resource_, &lock_, raster_source, raster_full_rect, raster_dirty_rect,
         scale, playback_settings, previous_content_id_, new_content_id);
   }
 
  private:
   OneCopyRasterBufferProvider* worker_pool_;
   const Resource* resource_;
   ResourceProvider::ScopedWriteLockGL lock_;
   uint64_t previous_content_id_;
@@ skipping 264 matching lines @@
     gl->OrderingBarrierCHROMIUM();
 
     // Generate sync token after the barrier for cross context synchronization.
     gpu::SyncToken sync_token;
     gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
     resource_lock->UpdateResourceSyncToken(sync_token);
   }
 }
 
 }  // namespace cc