Fix the MessageLoop type in case more than one ozone platform is built

ui/ozone/public/ozone_platform.h

 // 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.
 
 #ifndef UI_OZONE_PUBLIC_OZONE_PLATFORM_H_
 #define UI_OZONE_PUBLIC_OZONE_PLATFORM_H_
 
 #include <memory>
 
 #include "base/macros.h"
+#include "base/message_loop/message_loop.h"
 #include "ui/ozone/ozone_export.h"
 
 namespace display {
 class NativeDisplayDelegate;
 }
 
 namespace gfx {
 class Rect;
 }
 
@@ skipping 64 matching lines @@
   // Initializes the subsystems/resources necessary for rendering (i.e. GPU).
   // TODO(rjkroege): Remove deprecated entry point (http://crbug.com/620934)
   static void InitializeForGPU();
 
   // Initializes the subsystems for rendering but with additional properties
   // provided by |args| as with InitalizeForUI.
   static void InitializeForGPU(const InitParams& args);
 
   static OzonePlatform* GetInstance();
 
+  static base::MessageLoop::Type GetMessageLoopType();

[kylechar, 2017/01/17 21:54:53]

Add a comment to why this is here.

+
   // Factory getters to override in subclasses. The returned objects will be
   // injected into the appropriate layer at startup. Subclasses should not
   // inject these objects themselves. Ownership is retained by OzonePlatform.
   virtual ui::SurfaceFactoryOzone* GetSurfaceFactoryOzone() = 0;
   virtual ui::OverlayManagerOzone* GetOverlayManager() = 0;
   virtual ui::CursorFactoryOzone* GetCursorFactoryOzone() = 0;
   virtual ui::InputController* GetInputController() = 0;
   virtual IPC::MessageFilter* GetGpuMessageFilter();
   virtual ui::GpuPlatformSupportHost* GetGpuPlatformSupportHost() = 0;
   virtual std::unique_ptr<SystemInputInjector> CreateSystemInputInjector() = 0;
@@ skipping 22 matching lines @@
   static void CreateInstance();
 
   static OzonePlatform* instance_;
 
   DISALLOW_COPY_AND_ASSIGN(OzonePlatform);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PUBLIC_OZONE_PLATFORM_H_