Add fixed raster scale use counter histograms.

cc/trees/proxy_common.h

Index: cc/trees/proxy_common.h
diff --git a/cc/trees/proxy_common.h b/cc/trees/proxy_common.h
index 720ced29cbb8053e64ed381a4fc869f0ff6c6312..e35d3122e4f225bfa5696d84253f28874ecd54c3 100644
--- a/cc/trees/proxy_common.h
+++ b/cc/trees/proxy_common.h
@@ -26,12 +26,14 @@ struct CC_EXPORT BeginMainFrameAndCommitState {
   BeginMainFrameAndCommitState();
   ~BeginMainFrameAndCommitState();
 
-  unsigned int begin_frame_id;
+  unsigned int begin_frame_id = 0;
   BeginFrameArgs begin_frame_args;
   std::unique_ptr<BeginFrameCallbackList> begin_frame_callbacks;
   std::unique_ptr<ScrollAndScaleSet> scroll_info;
-  size_t memory_allocation_limit_bytes;
-  bool evicted_ui_resources;
+  size_t memory_allocation_limit_bytes = 0;
+  bool evicted_ui_resources = false;
+  bool has_fixed_raster_scale_blurry_content = false;
+  bool has_fixed_raster_scale_potential_performance_regression = false;
 
   void ToProtobuf(proto::BeginMainFrameAndCommitState* proto) const;
   void FromProtobuf(const proto::BeginMainFrameAndCommitState& proto);