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 86 matching lines @@
 void OzonePlatform::InitializeGPU(const InitParams& args) {
   InitializeGPU();
 }
 
 IPC::MessageFilter* OzonePlatform::GetGpuMessageFilter() {
   return nullptr;
 }
 void OzonePlatform::AddInterfaces(
     service_manager::InterfaceRegistry* registry) {}
 
+base::MessageLoop::Type OzonePlatform::GetMessageLoopType() {
+  // If we are be running Ozone X11 we need a UI loop to grab Expose events.
+  // See GLSurfaceGLX and https://crbug.com/326995.
+  return (!strcmp(GetOzonePlatformName(), "x11"))

[spang, 2017/01/19 16:31:55]

Don't use the platform name. Use a virtual function.

[kylechar, 2017/01/19 16:59:50]

Right, that's a better idea. We can't run OzonePlatform::InitializeForGPU()
before the main MessageLoop is created. Something will try and use the
MessageLoop then crash.

However, we can create the OzonePlatform instance without doing any
initialization if OzonePlatform::CreateInstance() is made public. It will get
still get initialized later and GetMessageLoopType() can be virtual.

[tonikitoo, 2017/02/07 16:18:37]

Done.

+             ? base::MessageLoop::TYPE_UI
+             : base::MessageLoop::TYPE_DEFAULT;
+}
+
 }  // namespace ui