cc: Trigger GPU rasterization based on a per-layer hint

cc/layers/picture_layer_impl.h

 // Copyright 2012 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_LAYERS_PICTURE_LAYER_IMPL_H_
 #define CC_LAYERS_PICTURE_LAYER_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 59 matching lines @@
   void SyncTiling(const PictureLayerTiling* tiling);
 
   // Mask-related functions
   void SetIsMask(bool is_mask);
   virtual ResourceProvider::ResourceId ContentsResourceId() const OVERRIDE;
 
   virtual size_t GPUMemoryUsageInBytes() const OVERRIDE;
 
   virtual void RunMicroBenchmark(MicroBenchmarkImpl* benchmark) OVERRIDE;
 
-  void SetShouldUseGpuRasterization(bool should_use_gpu_rasterization);
-  bool should_use_gpu_rasterization() const {
-    return should_use_gpu_rasterization_;
-  }
+  void SetHasGpuRasterizationHint(bool has_hint);
+  bool ShouldUseGpuRasterization() const;
 
  protected:
   PictureLayerImpl(LayerTreeImpl* tree_impl, int id);
   PictureLayerTiling* AddTiling(float contents_scale);
   void RemoveTiling(float contents_scale);
   void RemoveAllTilings();
   void SyncFromActiveLayer(const PictureLayerImpl* other);
   void ManageTilings(bool animating_transform_to_screen);
-  bool ShouldHaveLowResTiling() const {
-    return !should_use_gpu_rasterization();
-  }
+  bool ShouldHaveLowResTiling() const { return !ShouldUseGpuRasterization(); }
   virtual bool ShouldAdjustRasterScale(
       bool animating_transform_to_screen) const;
   virtual void RecalculateRasterScales(
       bool animating_transform_to_screen);
   void CleanUpTilingsOnActiveLayer(
       std::vector<PictureLayerTiling*> used_tilings);
   float MinimumContentsScale() const;
   float SnappedContentsScale(float new_contents_scale);
   void UpdateLCDTextStatus(bool new_status);
   void ResetRasterScale();
@@ skipping 37 matching lines @@
   float raster_source_scale_;
   float raster_contents_scale_;
   float low_res_raster_contents_scale_;
 
   bool raster_source_scale_was_animating_;
   bool is_using_lcd_text_;
   bool needs_post_commit_initialization_;
   // A sanity state check to make sure UpdateTilePriorities only gets called
   // after a CalculateContentsScale/ManageTilings.
   bool should_update_tile_priorities_;
-  bool should_use_gpu_rasterization_;
+  bool has_gpu_rasterization_hint_;
 
   friend class PictureLayer;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_IMPL_H_