Revert: cc: RenderSurfaceImpl tile mask layer.

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 68e92f74f9ffacb7a84a055c46b21ab1b93980e1..6cacd6fca499d11388277351b805970c77e541e6 100644
--- a/cc/layers/picture_layer.cc
+++ b/cc/layers/picture_layer.cc
@@ -146,11 +146,6 @@ bool PictureLayer::Update() {
 }
 
 void PictureLayer::SetLayerMaskType(LayerMaskType mask_type) {
-  // We do not allow converting SINGLE_TEXTURE_MASK to MULTI_TEXTURE_MASK in
-  // order to avoid rerastering when a mask's transform is being animated.
-  if (mask_type_ == LayerMaskType::SINGLE_TEXTURE_MASK &&
-      mask_type == LayerMaskType::MULTI_TEXTURE_MASK)
-    return;
   mask_type_ = mask_type;
 }