Revert of cc : Move screen space scale factor to root transform node

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 f0cc76d64905c89a01b8d1bc5c4108ae7e1f7624..9ae1138aa87c3ebd4c372037af0d5ae5597827cd 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1033,11 +1033,15 @@
           property_trees()->ComputeTransformToTarget(
               it->render_surface()->TransformTreeIndex(),
               occlusion_surface->EffectTreeIndex(), &draw_transform);
-          const EffectNode* occlusion_effect_node =
-              property_trees()->effect_tree.Node(
-                  occlusion_surface->EffectTreeIndex());
-          draw_property_utils::PostConcatSurfaceContentsScale(
-              occlusion_effect_node, &draw_transform);
+          // We don't have to apply surface contents scale when target is root.
+          if (occlusion_surface->EffectTreeIndex() !=
+              EffectTree::kContentsRootNodeId) {
+            const EffectNode* occlusion_effect_node =
+                property_trees()->effect_tree.Node(
+                    occlusion_surface->EffectTreeIndex());
+            draw_property_utils::PostConcatSurfaceContentsScale(
+                occlusion_effect_node, &draw_transform);
+          }
           const EffectNode* effect_node = property_trees()->effect_tree.Node(
               it->render_surface()->EffectTreeIndex());
           draw_property_utils::ConcatInverseSurfaceContentsScale(