Switch main GPU thread to Default Message Pump

content/gpu/gpu_main.cc

 // Copyright (c) 2012 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 <stddef.h>
 #include <stdlib.h>
 
 #include <memory>
 #include <utility>
 
@@ skipping 176 matching lines @@
       SEM_NOGPFAULTERRORBOX |
       SEM_NOOPENFILEERRORBOX);
 #elif defined(USE_X11)
   ui::SetDefaultX11ErrorHandlers();
 
 #endif
 
   logging::SetLogMessageHandler(GpuProcessLogMessageHandler);
 
 #if defined(OS_WIN)
-  // Use a UI message loop because ANGLE and the desktop GL platform can
-  // create child windows to render to.
-  base::MessagePumpForGpu::InitFactory();
-  base::MessageLoop main_message_loop(base::MessageLoop::TYPE_UI);
+  // OK to use default non-UI message loop because all GPU windows run on
+  // dedicated thread.
+  base::MessageLoop main_message_loop(base::MessageLoop::TYPE_DEFAULT);
 #elif defined(USE_X11)
   // We need a UI loop so that we can grab the Expose events. See GLSurfaceGLX
   // and https://crbug.com/326995.
   base::MessageLoop main_message_loop(base::MessageLoop::TYPE_UI);
   std::unique_ptr<ui::PlatformEventSource> event_source =
       ui::PlatformEventSource::CreateDefault();
 #elif defined(USE_OZONE) && defined(OZONE_X11)
   // If we might be running Ozone X11 we need a UI loop to grab Expose events.
   // See GLSurfaceGLX and https://crbug.com/326995.
   base::MessageLoop main_message_loop(base::MessageLoop::TYPE_UI);
@@ skipping 130 matching lines @@
     return true;
   }
 
   return false;
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace.
 
 }  // namespace content