cc: Allow changing mask type when pushing properties.

cc/layers/picture_layer.cc

Index: cc/layers/picture_layer.cc
diff --git a/cc/layers/picture_layer.cc b/cc/layers/picture_layer.cc
index f22545cc29f605786eb284dd54d8cb781c49dba4..146296d1eed9d14e5fc625f32e478deeb7040ff0 100644
--- a/cc/layers/picture_layer.cc
+++ b/cc/layers/picture_layer.cc
@@ -50,8 +50,7 @@ void PictureLayer::PushPropertiesTo(LayerImpl* base_layer) {
   Layer::PushPropertiesTo(base_layer);
   TRACE_EVENT0("cc", "PictureLayer::PushPropertiesTo");
   PictureLayerImpl* layer_impl = static_cast<PictureLayerImpl*>(base_layer);
-  // TODO(danakj): Make mask_type_ a constructor parameter for PictureLayer.
-  DCHECK_EQ(layer_impl->mask_type(), mask_type());
+  layer_impl->SetLayerMaskType(mask_type());
   DropRecordingSourceContentIfInvalid();
 
   layer_impl->SetNearestNeighbor(picture_layer_inputs_.nearest_neighbor);