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

ui/ozone/public/ozone_platform.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 "base/command_line.h"
 #include "base/logging.h"
 #include "base/trace_event/trace_event.h"
 #include "ui/events/devices/device_data_manager.h"
 #include "ui/ozone/platform_object.h"
 #include "ui/ozone/platform_selection.h"
@@ skipping 22 matching lines @@
 }
 
 // static
 void OzonePlatform::InitializeForUI() {
   const InitParams params;
   OzonePlatform::InitializeForUI(params);
 }
 
 // static
 void OzonePlatform::InitializeForUI(const InitParams& args) {
-  CreateInstance();
+  EnsureInstance();
   if (g_platform_initialized_ui)
     return;
   g_platform_initialized_ui = true;
   instance_->InitializeUI(args);
   // This is deliberately created after initializing so that the platform can
   // create its own version of DDM.
   DeviceDataManager::CreateInstance();
 }
 
 // static
 void OzonePlatform::InitializeForGPU() {
   const InitParams params;
   OzonePlatform::InitializeForGPU(params);
 }
 
 // static
 void OzonePlatform::InitializeForGPU(const InitParams& args) {
-  CreateInstance();
+  EnsureInstance();
   if (g_platform_initialized_gpu)
     return;
   g_platform_initialized_gpu = true;
   instance_->InitializeGPU(args);
 }
 
 // static
 OzonePlatform* OzonePlatform::GetInstance() {
   DCHECK(instance_) << "OzonePlatform is not initialized";
   return instance_;
 }
 
 // static
-void OzonePlatform::CreateInstance() {
+OzonePlatform* OzonePlatform::EnsureInstance() {
   if (!instance_) {
     TRACE_EVENT1("ozone",
                  "OzonePlatform::Initialize",
                  "platform",
                  GetOzonePlatformName());
     std::unique_ptr<OzonePlatform> platform =
         PlatformObject<OzonePlatform>::Create();
 
     // TODO(spang): Currently need to leak this object.
     OzonePlatform* pl = platform.release();
     DCHECK_EQ(instance_, pl);
   }
+  return instance_;
 }
 
 // static
 OzonePlatform* OzonePlatform::instance_;
 
 // Convenience methods to facilitate transitionning to new API.
 void OzonePlatform::InitializeUI(const InitParams& args) {
   InitializeUI();
 }
+
 void OzonePlatform::InitializeGPU(const InitParams& args) {
   InitializeGPU();
 }
 
 IPC::MessageFilter* OzonePlatform::GetGpuMessageFilter() {
   return nullptr;
 }
+
+base::MessageLoop::Type OzonePlatform::GetMessageLoopTypeForGpu() {
+  return base::MessageLoop::TYPE_DEFAULT;
+}
+
 void OzonePlatform::AddInterfaces(
     service_manager::InterfaceRegistry* registry) {}
 
 }  // namespace ui