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

gpu/command_buffer/service/gpu_processor_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/gfx/gl/gl_context.h"
 #include "gpu/command_buffer/service/gpu_processor.h"
 
 using ::base::SharedMemory;
 
 namespace gpu {
@@ skipping 75 matching lines @@
   decoder_->UpdateOffscreenFrameBufferSize();
   return surface_->SetTransportDIBSize(size);
 }
 
 void GPUProcessor::SetTransportDIBAllocAndFree(
       Callback2<size_t, TransportDIB::Handle*>::Type* allocator,
       Callback1<TransportDIB::Id>::Type* deallocator) {
   surface_->SetTransportDIBAllocAndFree(allocator, deallocator);
 }
 
+uint64 GPUProcessor::GetSurfaceId() {
+  if (!surface_.get())
+    return 0;
+  return surface_->GetSurfaceId();
+}
+
 void GPUProcessor::WillSwapBuffers() {
   DCHECK(decoder_.get());
   DCHECK(decoder_->GetGLContext());
   DCHECK(decoder_->GetGLContext()->IsCurrent());
 
   if (surface_.get()) {
     surface_->SwapBuffers();
   }
 
   if (wrapped_swap_buffers_callback_.get()) {
     wrapped_swap_buffers_callback_->Run();
   }
 }
 
 }  // namespace gpu