Add fixed raster scale use counter histograms.

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index f21f215746883fc24a2c249bb7c7fc86af5853ec..f5bb4801ed07d6e363991463417ebb8987a0d51b 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1952,6 +1952,14 @@ VideoFrameControllerClient* LayerTreeImpl::GetVideoFrameControllerClient()
   return layer_tree_host_impl_;
 }
 
+void LayerTreeImpl::SetFixedRasterScaleHasBlurryContent() {
+  layer_tree_host_impl_->set_fixed_raster_scale_has_blurry_content();
+}
+
+void LayerTreeImpl::SetFixedRasterScaleAttemptedToChangeScale() {
+  layer_tree_host_impl_->SetFixedRasterScaleAttemptedToChangeScale();
+}
+
 void LayerTreeImpl::SetPendingPageScaleAnimation(
     std::unique_ptr<PendingPageScaleAnimation> pending_animation) {
   pending_page_scale_animation_ = std::move(pending_animation);