cc: Reduce surface contents scale adjustments.

cc/trees/property_tree.cc

Index: cc/trees/property_tree.cc
diff --git a/cc/trees/property_tree.cc b/cc/trees/property_tree.cc
index ab426546edbf1bac2b285b4b012b2ad81ce16868..f33b6f980de319eef8648b7bc4c24bb75c46d092 100644
--- a/cc/trees/property_tree.cc
+++ b/cc/trees/property_tree.cc
@@ -841,10 +841,14 @@ void EffectTree::UpdateSurfaceContentsScale(EffectNode* effect_node) {
   }
 
   TransformTree& transform_tree = property_trees()->transform_tree;
-  float layer_scale_factor = transform_tree.device_scale_factor() *
-                             transform_tree.device_transform_scale_factor();
   TransformNode* transform_node =
       transform_tree.Node(effect_node->transform_id);
+  if (transform_node->is_currently_animating) {

[ajuma, 2017/04/04 21:41:11]

Would it make sense to tie this to
LayerTreeSettings::layer_transforms_should_scale_layer_contents == false instead
of to whether we're animating?

[reveman, 2017/04/05 13:20:15]

Makes sense. Done.

+    effect_node->surface_contents_scale = gfx::Vector2dF(1.0f, 1.0f);

[ajuma, 2017/04/04 21:41:11]

Is device scale factor a better choice than 1 here? (to match the ideal contents
scale of layers)

[reveman, 2017/04/05 13:20:15]

Yes, it is. Done.

+    return;
+  }
+  float layer_scale_factor = transform_tree.device_scale_factor() *
+                             transform_tree.device_transform_scale_factor();
   if (transform_node->in_subtree_of_page_scale_layer)
     layer_scale_factor *= transform_tree.page_scale_factor();
   effect_node->surface_contents_scale =