Add fixed raster scale use counter histograms.

cc/proto/begin_main_frame_and_commit_state.proto

 // Copyright 2016 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.
 
 syntax = "proto2";
 
 import "vector2d.proto";
 import "vector2df.proto";
 
 option optimize_for = LITE_RUNTIME;
@@ skipping 29 matching lines @@
   optional BeginFrameArgsType type = 4;
   optional bool on_critical_path = 5;
 }
 
 message BeginMainFrameAndCommitState {
   optional int64 begin_frame_id = 1;
   optional BeginFrameArgs begin_frame_args = 2;
   optional ScrollAndScaleSet scroll_info = 3;
   optional int64 memory_allocation_limit_bytes = 4;
   optional bool evicted_ui_resources = 5;
-}
+  optional bool has_fixed_raster_scale_blurry_content = 6;
+  optional bool has_fixed_raster_scale_potential_performance_regression = 7;
+}