Make cc::CompositorFrames movable [Part 1 of 2]

cc/output/compositor_frame.h

 // Copyright 2012 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_OUTPUT_COMPOSITOR_FRAME_H_
 #define CC_OUTPUT_COMPOSITOR_FRAME_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
 #include "cc/output/compositor_frame_metadata.h"
 #include "cc/output/delegated_frame_data.h"
 #include "cc/output/gl_frame_data.h"
 
 namespace cc {
 
 // A CompositorFrame struct contains the complete output of a compositor meant
-// for display.
-// TODO(fsamuel): Write more here.
+// for display. A CompositorFrame consists of a series of DrawQuads that
+// describe placement of textures, solid colors, overlays and other
+// CompositorFrames within an area specified by the parent compositor. DrawQuads
+// may share common data referred to as SharedQuadState. A CompositorFrame also
+// has |metadata| that refers to global graphical state associated with this
+// frame.
 class CC_EXPORT CompositorFrame {
  public:
   CompositorFrame();
+  CompositorFrame(CompositorFrame&& other);
   ~CompositorFrame();
 
+  CompositorFrame& operator=(CompositorFrame&& other);
+
   CompositorFrameMetadata metadata;
   std::unique_ptr<DelegatedFrameData> delegated_frame_data;
   std::unique_ptr<GLFrameData> gl_frame_data;
 
-  void AssignTo(CompositorFrame* target);
-
  private:
   DISALLOW_COPY_AND_ASSIGN(CompositorFrame);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_COMPOSITOR_FRAME_H_