Replacing SurfaceReferenceBase and SequenceSurfaceReference with Closures

cc/surfaces/sequence_surface_reference_factory.h

 // Copyright 2016 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 CC_SURFACES_SEQUENCE_SURFACE_REFERENCE_FACTORY_H_
 #define CC_SURFACES_SEQUENCE_SURFACE_REFERENCE_FACTORY_H_
 
-#include "cc/output/compositor_frame_metadata.h"
-#include "cc/surfaces/surface_reference_base.h"
 #include "cc/surfaces/surface_reference_factory.h"
+#include "cc/surfaces/surface_sequence.h"
 #include "cc/surfaces/surfaces_export.h"
 
 namespace cc {
 
-// A surface reference factory that generates references which internally
-// use SurfaceSequence.
+// A surface reference factory that uses SurfaceSequence.
 class CC_SURFACES_EXPORT SequenceSurfaceReferenceFactory
     : public NON_EXPORTED_BASE(SurfaceReferenceFactory) {
  public:
   SequenceSurfaceReferenceFactory() = default;
 
-  std::unique_ptr<SurfaceReferenceBase> CreateReference(
-      SurfaceReferenceOwner* owner,
-      const SurfaceId& surface_id) const override;
+  // SurfaceReferenceFactory implementation:
+  base::Closure CreateReference(SurfaceReferenceOwner* owner,
+                                const SurfaceId& surface_id) const override;
 
  protected:
   ~SequenceSurfaceReferenceFactory() override = default;
 
  private:
   virtual void RequireSequence(const SurfaceId& surface_id,
                                const SurfaceSequence& sequence) const = 0;
   virtual void SatisfySequence(const SurfaceSequence& sequence) const = 0;
 
-  // SurfaceReferenceFactory implementation:
-  void DestroyReference(SurfaceReferenceBase* surface_ref) const override;
-
   DISALLOW_COPY_AND_ASSIGN(SequenceSurfaceReferenceFactory);
 };
 
 }  // namespace cc
 
 #endif  // CC_SURFACES_SEQUENCE_SURFACE_REFERENCE_FACTORY_H_