Let every "accelerated IO surface swapped" message have an identifier of the surface.

app/surface/accelerated_surface_mac.h

 // Copyright (c) 2010 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 APP_SURFACE_ACCELERATED_SURFACE_MAC_H_
 #define APP_SURFACE_ACCELERATED_SURFACE_MAC_H_
 #pragma once
 
 #include <CoreFoundation/CoreFoundation.h>
 
@@ skipping 40 matching lines @@
   void Destroy();
 
   // These methods are used only once the accelerated surface is initialized.
 
   // Sets the accelerated surface to the given size, creating a new one if
   // the height or width changes. Returns a unique id of the IOSurface to
   // which the surface is bound, or 0 if no changes were made or an error
   // occurred. MakeCurrent() will have been called on the new surface.
   uint64 SetSurfaceSize(const gfx::Size& size);
 
+  // Returns the id of this surface's IOSruface, or 0 for
+  // transport DIB surfaces.
+  uint64 GetSurfaceId();
+
   // Sets the GL context to be the current one for drawing. Returns true if
   // it succeeded.
   bool MakeCurrent();
   // Clear the surface to be transparent. Assumes the caller has already called
   // MakeCurrent().
   void Clear(const gfx::Rect& rect);
   // Call after making changes to the surface which require a visual update.
   // Makes the rendering show up in other processes. Assumes the caller has
   // already called MakeCurrent().
   //
@@ skipping 53 matching lines @@
   // speaking, we do not need to allocate a GL context all of the
   // time. We only need one if (a) we are using the IOSurface code
   // path, or (b) if we are allocating an FBO internally.
   scoped_ptr<gfx::GLContext> gl_context_;
   // Either |io_surface_| or |transport_dib_| is a valid pointer, but not both.
   // |io_surface_| is non-NULL if the IOSurface APIs are supported (Mac OS X
   // 10.6 and later).
   // TODO(dspringer,kbr): Should the GPU backing store be encapsulated in its
   // own class so all this implementation detail is hidden?
   base::mac::ScopedCFTypeRef<CFTypeRef> io_surface_;
+
+  // The id of |io_surface_| or 0 if that's NULL.
+  uint64 io_surface_id_;
+
   // TODO(dspringer): If we end up keeping this TransportDIB mechanism, this
   // should really be a scoped_ptr_malloc<>, with a deallocate functor that
   // runs |dib_free_callback_|.  I was not able to figure out how to
   // make this work (or even compile).
   scoped_ptr<TransportDIB> transport_dib_;
   gfx::Size surface_size_;
   // TODO(kbr): the FBO management should not be in this class at all.
   // However, if it is factored out, care needs to be taken to not
   // introduce another copy of the color data on the GPU; the direct
   // binding of the internal texture to the IOSurface saves a copy.
   bool allocate_fbo_;
   // If the IOSurface code path is being used, then this texture
   // object is always allocated. Otherwise, it is only allocated if
   // the user requests an FBO be allocated.
   GLuint texture_;
   // The FBO and renderbuffer are only allocated if allocate_fbo_ is
   // true.
   GLuint fbo_;
   GLuint depth_stencil_renderbuffer_;
   // Allocate a TransportDIB in the renderer.
   scoped_ptr<Callback2<size_t, TransportDIB::Handle*>::Type>
       dib_alloc_callback_;
   scoped_ptr<Callback1<TransportDIB::Id>::Type> dib_free_callback_;
 };
 
 #endif  // APP_SURFACE_ACCELERATED_SURFACE_MAC_H_