cc: Compute sublayer scale from effect tree

cc/trees/property_tree_unittest.cc

Index: cc/trees/property_tree_unittest.cc
diff --git a/cc/trees/property_tree_unittest.cc b/cc/trees/property_tree_unittest.cc
index f5f1e058459835d775ecd0ddd77c74fea8cae9ef..0cc190f791ed4d8fcf984bf713e4a5d88b22e085 100644
--- a/cc/trees/property_tree_unittest.cc
+++ b/cc/trees/property_tree_unittest.cc
@@ -186,6 +186,7 @@ TEST(PropertyTreeSerializationTest, EffectNodeDataSerialization) {
   original.mask_layer_id = 6;
   original.replica_layer_id = 10;
   original.replica_mask_layer_id = 9;
+  original.sublayer_scale = gfx::Vector2dF(0.5f, 0.5f);
 
   proto::TreeNode proto;
   original.ToProtobuf(&proto);