ozone: Add post message loop initialization hook

ui/ozone/platform/drm/ozone_platform_drm.cc

 // Copyright 2013 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 "ui/ozone/platform/drm/ozone_platform_drm.h"
 
 #include "base/at_exit.h"
 #include "base/thread_task_runner_handle.h"
 #include "ui/base/cursor/ozone/bitmap_cursor_factory_ozone.h"
 #include "ui/events/ozone/device/device_manager.h"
@@ skipping 112 matching lines @@
         cursor_.get(), device_manager_.get(),
         KeyboardLayoutEngineManager::GetKeyboardLayoutEngine()));
 
     if (!gpu_helper_.Initialize(base::ThreadTaskRunnerHandle::Get(),
                                 base::ThreadTaskRunnerHandle::Get()))
       LOG(FATAL) << "Failed to initialize dummy channel.";
   }
 
   void InitializeGPU() override {}
 
+  void InitializeGpuPostMainLoop() override {}
+
  private:
   // Objects in the "GPU" process.
   scoped_ptr<GpuLock> gpu_lock_;
   scoped_refptr<DrmDevice> drm_;
   scoped_ptr<DrmDeviceManager> drm_device_manager_;
   scoped_ptr<DrmBufferGenerator> buffer_generator_;
   scoped_ptr<ScreenManager> screen_manager_;
   scoped_ptr<DrmGpuPlatformSupport> gpu_platform_support_;
 
   // Objects in the "Browser" process.
@@ skipping 21 matching lines @@
 
 OzonePlatform* CreateOzonePlatformDri() {
   return new OzonePlatformDrm;
 }
 
 OzonePlatform* CreateOzonePlatformDrm() {
   return new OzonePlatformDrm;
 }
 
 }  // namespace ui