Change transport dib API to not make copies of SharedMemoryHandle.

ui/surface/transport_dib.h

 // Copyright (c) 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 UI_SURFACE_TRANSPORT_DIB_H_
 #define UI_SURFACE_TRANSPORT_DIB_H_
 
 #include "base/basictypes.h"
 #include "base/memory/shared_memory.h"
 #include "ui/surface/surface_export.h"
@@ skipping 117 matching lines @@
 
   // Return the maximum size of the shared memory. This is not the amount of
   // data which is valid, you have to know that via other means, this is simply
   // the maximum amount that /could/ be valid.
   size_t size() const { return size_; }
 
   // Return the identifier which can be used to refer to this shared memory
   // on the wire.
   Id id() const;
 
-  // Return a handle to the underlying shared memory. This can be sent over the
-  // wire to give this transport DIB to another process.
-  Handle handle() const;
+  // Returns a pointer to the SharedMemory object that backs the transport dib.
+  base::SharedMemory* shared_memory();
 
  private:
   TransportDIB();
 
   // Verifies that the dib can hold a canvas of the requested dimensions.
   bool VerifyCanvasSize(int w, int h);
 
   explicit TransportDIB(base::SharedMemoryHandle dib);
   base::SharedMemory shared_memory_;
   uint32 sequence_num_;
   size_t size_;  // length, in bytes
 
   DISALLOW_COPY_AND_ASSIGN(TransportDIB);
 };
 
 #endif  // UI_SURFACE_TRANSPORT_DIB_H_