Always use a UI message loop in the GPU process on Windows.

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 <stdlib.h>
 
 #if defined(OS_WIN)
 #include <dwmapi.h>
 #include <windows.h>
 #endif
@@ skipping 137 matching lines @@
   // safely until the IPC channel is set up, because the detection of
   // early return of a child process is implemented using an IPC
   // channel error. If the IPC channel is not fully set up between the
   // browser and GPU process, and the GPU process crashes or exits
   // early, the browser process will never detect it.  For this reason
   // we defer tearing down the GPU process until receiving the
   // GpuMsg_Initialize message from the browser.
   bool dead_on_arrival = false;
 
 #if defined(OS_WIN)
-  base::MessageLoop::Type message_loop_type = base::MessageLoop::TYPE_IO;
-  // Unless we're running on desktop GL, we don't need a UI message
-  // loop, so avoid its use to work around apparent problems with some
-  // third-party software.
-  if (command_line.HasSwitch(switches::kUseGL) &&
-      command_line.GetSwitchValueASCII(switches::kUseGL) ==
-          gfx::kGLImplementationDesktopName) {
-    message_loop_type = base::MessageLoop::TYPE_UI;
-  }
-  base::MessageLoop main_message_loop(message_loop_type);
+  // Use a UI message loop because ANGLE and the desktop GL platform can
+  // create child windows to render to.
+  base::MessageLoop main_message_loop(base::MessageLoop::TYPE_UI);
 #elif defined(OS_LINUX) && 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);
   scoped_ptr<ui::PlatformEventSource> event_source =
       ui::PlatformEventSource::CreateDefault();
 #elif defined(OS_LINUX)
   base::MessageLoop main_message_loop(base::MessageLoop::TYPE_DEFAULT);
 #elif defined(OS_MACOSX)
   // This is necessary for CoreAnimation layers hosted in the GPU process to be
@@ skipping 359 matching lines @@
     return true;
   }
 
   return false;
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace.
 
 }  // namespace content