Only Record Ugliness Histogram for Compositor Side Changes

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 8818f0ec34574ed944e67bed0e1a24ae9d25c2ba..00e17949a48269772d30ecfe448ecf531dd02a3a 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -90,6 +90,7 @@ LayerTreeImpl::LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl)
       needs_update_draw_properties_(true),
       needs_full_tree_sync_(true),
       next_activation_forces_redraw_(false),
+      frames_have_been_drawn_(0),
       render_surface_layer_list_id_(0) {
 }
 
@@ -237,6 +238,8 @@ void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
             target_tree->root_layer(), hud_layer()->id())));
   else
     target_tree->set_hud_layer(NULL);
+
+  target_tree->frames_have_been_drawn_ = 1;
 }
 
 LayerImpl* LayerTreeImpl::InnerViewportContainerLayer() const {