Avoid destroying surface before the parent surface stops referencing it.

mojo/aura/surface_context_factory.cc

 // Copyright 2014 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 "mojo/aura/surface_context_factory.h"
 
 #include "cc/output/output_surface.h"
 #include "cc/resources/shared_bitmap_manager.h"
+#include "cc/surfaces/surface_id_allocator.h"
 #include "mojo/public/interfaces/application/shell.mojom.h"
 #include "mojo/services/public/cpp/view_manager/view.h"
 #include "ui/compositor/reflector.h"
 
 namespace mojo {
 
 SurfaceContextFactory::SurfaceContextFactory(Shell* shell, View* view)
     : surface_binding_(shell, view) {
 }
 
@@ skipping 29 matching lines @@
 }
 
 cc::SharedBitmapManager* SurfaceContextFactory::GetSharedBitmapManager() {
   return nullptr;
 }
 
 base::MessageLoopProxy* SurfaceContextFactory::GetCompositorMessageLoop() {
   return nullptr;
 }
 
+scoped_ptr<cc::SurfaceIdAllocator>
+SurfaceContextFactory::CreateSurfaceIdAllocator() {
+  return nullptr;
+}
+
 }  // namespace mojo