Add fixed raster scale use counter histograms.

cc/test/fake_layer_tree_host_client.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_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_
 #define CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_
 
 #include <memory>
 
 #include "cc/input/input_handler.h"
@@ skipping 36 matching lines @@
   void WillCommit() override {}
   void DidCommit() override {}
   void DidCommitAndDrawFrame() override {}
   void DidCompleteSwapBuffers() override {}
   void DidCompletePageScaleAnimation() override {}
 
   // LayerTreeHostSingleThreadClient implementation.
   void DidPostSwapBuffers() override {}
   void DidAbortSwapBuffers() override {}
 
+  void ReportFixedRasterScaleUseCounters(

[danakj, 2016/05/05 00:09:49]

this should be part of the LayerTreeHostClient impl block

[vmpstr, 2016/05/05 01:33:50]

Done.

+      bool has_blurry_content,
+      bool has_potential_performance_regression) override {}
+
  private:
   bool use_software_rendering_;
   bool use_delegating_renderer_;
 
   LayerTreeHost* host_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_