Add fixed raster scale use counter histograms.

cc/trees/layer_tree_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_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 100 matching lines @@
   void DidAnimateScrollOffset();
   bool use_gpu_rasterization() const;
   GpuRasterizationStatus GetGpuRasterizationStatus() const;
   bool create_low_res_tiling() const;
   bool RequiresHighResToDraw() const;
   bool SmoothnessTakesPriority() const;
   VideoFrameControllerClient* GetVideoFrameControllerClient() const;
   AnimationHost* animation_host() const {
     return layer_tree_host_impl_->animation_host();
   }
+  void SetFixedRasterScaleHasBlurryContent();
+  void SetFixedRasterScaleAttemptedToChangeScale();
 
   // Tree specific methods exposed to layer-impl tree.
   // ---------------------------------------------------------------------------
   void SetNeedsRedraw();
 
   // Tracing methods.
   // ---------------------------------------------------------------------------
   void GetAllPrioritizedTilesForTracing(
       std::vector<PrioritizedTile>* prioritized_tiles) const;
   void AsValueInto(base::trace_event::TracedValue* dict) const;
@@ skipping 457 matching lines @@
 
   std::unique_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_