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

app/surface/accelerated_surface_mac.cc

 // 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.
 
 #include "app/surface/accelerated_surface_mac.h"
 
 #include "app/gfx/gl/gl_bindings.h"
 #include "app/gfx/gl/gl_implementation.h"
 #include "app/surface/io_surface_support_mac.h"
 #include "base/logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "gfx/rect.h"
 
 AcceleratedSurface::AcceleratedSurface()
-    : allocate_fbo_(false),
+    : io_surface_id_(0),
+      allocate_fbo_(false),
       texture_(0),
       fbo_(0),
       depth_stencil_renderbuffer_(0) {
 }
 
 bool AcceleratedSurface::Initialize(gfx::GLContext* share_context,
                                     bool allocate_fbo) {
   allocate_fbo_ = allocate_fbo;
 
   // Ensure GL is initialized before trying to create an offscreen GL context.
@@ skipping 233 matching lines @@
   }
   surface_size_ = size;
 
   // Now send back an identifier for the IOSurface. We originally
   // intended to send back a mach port from IOSurfaceCreateMachPort
   // but it looks like Chrome IPC would need to be modified to
   // properly send mach ports between processes. For the time being we
   // make our IOSurfaces global and send back their identifiers. On
   // the browser process side the identifier is reconstituted into an
   // IOSurface for on-screen rendering.
-  return io_surface_support->IOSurfaceGetID(io_surface_);
+  io_surface_id_ = io_surface_support->IOSurfaceGetID(io_surface_);
+  return io_surface_id_;
+}
+
+uint64 AcceleratedSurface::GetSurfaceId() {
+  return io_surface_id_;
 }
 
 TransportDIB::Handle AcceleratedSurface::SetTransportDIBSize(
     const gfx::Size& size) {
   if (surface_size_ == size) {
     // Return an invalid handle to indicate to the caller that no new backing
     // store allocation occurred.
     return TransportDIB::DefaultHandleValue();
   }
   surface_size_ = size;
@@ skipping 41 matching lines @@
   }
   return transport_dib_->handle();
 }
 
 void AcceleratedSurface::SetTransportDIBAllocAndFree(
     Callback2<size_t, TransportDIB::Handle*>::Type* allocator,
     Callback1<TransportDIB::Id>::Type* deallocator) {
   dib_alloc_callback_.reset(allocator);
   dib_free_callback_.reset(deallocator);
 }