Adds a TransportDIB::Id value that is explicitly invalid and use it when compositing

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"
@@ skipping 289 matching lines @@
     dib_free_callback_->Run(transport_dib_->id());
   }
   transport_dib_.reset();
 
   // Ask the renderer to create a TransportDIB.
   size_t dib_size = size.width() * 4 * size.height();  // 4 bytes per pixel.
   TransportDIB::Handle dib_handle;
   if (dib_alloc_callback_.get()) {
     dib_alloc_callback_->Run(dib_size, &dib_handle);
   }
-  if (!TransportDIB::is_valid(dib_handle)) {
+  if (!TransportDIB::is_valid_handle(dib_handle)) {
     // If the allocator fails, it means the DIB was not created in the browser,
     // so there is no need to run the deallocator here.
     return TransportDIB::DefaultHandleValue();
   }
   transport_dib_.reset(TransportDIB::Map(dib_handle));
   if (transport_dib_.get() == NULL) {
     // TODO(dspringer): if the Map() fails, should the deallocator be run so
     // that the DIB is deallocated in the browser?
     return TransportDIB::DefaultHandleValue();
   }
@@ skipping 17 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);
 }