Use an X event loop in the GPU process on Linux.

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 128 matching lines @@
   base::MessageLoop::Type message_loop_type = base::MessageLoop::TYPE_IO;
 #if defined(OS_WIN)
   // 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;
   }
+#elif defined(TOOLKIT_GTK)
+  message_loop_type = base::MessageLoop::TYPE_GPU;
 #elif defined(OS_LINUX)
   message_loop_type = base::MessageLoop::TYPE_DEFAULT;
 #endif
 
   base::MessageLoop main_message_loop(message_loop_type);
   base::PlatformThread::SetName("CrGpuMain");
 
   // In addition to disabling the watchdog if the command line switch is
   // present, disable the watchdog on valgrind because the code is expected
   // to run slowly in that case.
@@ skipping 288 matching lines @@
     return true;
   }
 
   return false;
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace.
 
 }  // namespace content