cc: Add traces for identification of raster buffer.

cc/raster/zero_copy_raster_buffer_provider.cc

 // Copyright 2013 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/zero_copy_raster_buffer_provider.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 
@@ skipping 18 matching lines @@
       : lock_(resource_provider, resource->id()), resource_(resource) {}
 
   // 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", "ZeroCopyRasterBuffer::Playback");
     gfx::GpuMemoryBuffer* buffer = lock_.GetGpuMemoryBuffer();
     if (!buffer)
       return;
 
     DCHECK_EQ(1u, gfx::NumberOfPlanesForBufferFormat(buffer->GetFormat()));
     bool rv = buffer->Map();
     DCHECK(rv);
     DCHECK(buffer->memory(0));
     // RasterBufferProvider::PlaybackToMemory only supports unsigned strides.
     DCHECK_GE(buffer->stride(0), 0);
@@ skipping 62 matching lines @@
 }
 
 bool ZeroCopyRasterBufferProvider::GetResourceRequiresSwizzle(
     bool must_support_alpha) const {
   return ResourceFormatRequiresSwizzle(GetResourceFormat(must_support_alpha));
 }
 
 void ZeroCopyRasterBufferProvider::Shutdown() {}
 
 }  // namespace cc