Mozart: Ensure time always runs forward.

services/gfx/compositor/graph/resources.h

 // 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.
 
 #ifndef SERVICES_GFX_COMPOSITOR_GRAPH_RESOURCES_H_
 #define SERVICES_GFX_COMPOSITOR_GRAPH_RESOURCES_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
 #include "mojo/services/gfx/composition/interfaces/resources.mojom.h"
 #include "services/gfx/compositor/render/render_image.h"
 
 namespace compositor {
 
-class SceneDef;
-
 // Base class for resources in a scene graph.
 //
 // Instances of this class are immutable and reference counted so they may
 // be shared by multiple versions of the same scene.
 class Resource : public base::RefCounted<Resource> {
  public:
   enum class Type { kScene, kImage };
 
   Resource();
 
   // Gets the resource type.
   virtual Type type() const = 0;
 
  protected:
   friend class base::RefCounted<Resource>;
   virtual ~Resource();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Resource);
 };
 
 // A resource which represents a reference to a specified scene.
 class SceneResource : public Resource {
  public:
-  SceneResource(const mojo::gfx::composition::SceneToken& scene_token,
-                const base::WeakPtr<SceneDef>& referenced_scene);
+  explicit SceneResource(const mojo::gfx::composition::SceneToken& scene_token);
 
   Type type() const override;
 
   const mojo::gfx::composition::SceneToken& scene_token() const {
     return scene_token_;
   }
 
-  // The referenced scene, may be null if the scene is unavailable.
-  const base::WeakPtr<SceneDef>& referenced_scene() const {
-    return referenced_scene_;
-  }
-
-  // Returns a copy of the resource without its referenced scene.
-  scoped_refptr<const SceneResource> Unlink() const;
-
  protected:
   ~SceneResource() override;
 
  private:
   mojo::gfx::composition::SceneToken scene_token_;
-  base::WeakPtr<SceneDef> referenced_scene_;
 
   DISALLOW_COPY_AND_ASSIGN(SceneResource);
 };
 
 // A resource which represents a refrence to a specified image.
 class ImageResource : public Resource {
  public:
   explicit ImageResource(const scoped_refptr<RenderImage>& image);
 
   Type type() const override;
 
   // The referenced image, never null.
   const scoped_refptr<RenderImage>& image() const { return image_; }
 
  protected:
   ~ImageResource() override;
 
  private:
   scoped_refptr<RenderImage> image_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageResource);
 };
 
 }  // namespace compositor
 
 #endif  // SERVICES_GFX_COMPOSITOR_GRAPH_RESOURCES_H_