Mozart: Ensure time always runs forward.

services/gfx/compositor/graph/resources.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/gfx/compositor/graph/resources.h"
 
 #include "base/logging.h"
 
 namespace compositor {
 
 Resource::Resource() {}
 
 Resource::~Resource() {}
 
 SceneResource::SceneResource(
-    const mojo::gfx::composition::SceneToken& scene_token,
-    const base::WeakPtr<SceneDef>& referenced_scene)
-    : scene_token_(scene_token), referenced_scene_(referenced_scene) {}
+    const mojo::gfx::composition::SceneToken& scene_token)
+    : scene_token_(scene_token) {}
 
 SceneResource::~SceneResource() {}
 
-scoped_refptr<const SceneResource> SceneResource::Unlink() const {
-  return new SceneResource(scene_token_, base::WeakPtr<SceneDef>());
-}
-
 Resource::Type SceneResource::type() const {
   return Type::kScene;
 }
 
 ImageResource::ImageResource(const scoped_refptr<RenderImage>& image)
     : image_(image) {
   DCHECK(image);
 }
 
 ImageResource::~ImageResource() {}
 
 Resource::Type ImageResource::type() const {
   return Type::kImage;
 }
 
 }  // namespace compositor