cc: don't add low-res tiling to GPU rasterized layers.

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 67 matching lines @@
     return should_use_gpu_rasterization_;
   }
 
  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();
+  }
   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 49 matching lines @@
   bool should_update_tile_priorities_;
   bool should_use_gpu_rasterization_;
 
   friend class PictureLayer;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_IMPL_H_