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

base/message_loop/message_loop.cc

 // Copyright 2013 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/message_loop/message_loop.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 166 matching lines @@
 #error Not implemented
 #endif
 
   if (type_ == TYPE_UI) {
     if (message_pump_for_ui_factory_)
       pump_.reset(message_pump_for_ui_factory_());
     else
       pump_.reset(MESSAGE_PUMP_UI);
   } else if (type_ == TYPE_IO) {
     pump_.reset(MESSAGE_PUMP_IO);
+#if defined(TOOLKIT_GTK)
+  } else if (type_ == TYPE_GPU) {
+    pump_.reset(new MessagePumpX11());
+#endif
 #if defined(OS_ANDROID)
   } else if (type_ == TYPE_JAVA) {
     pump_.reset(MESSAGE_PUMP_UI);
 #endif
   } else {
     DCHECK_EQ(TYPE_DEFAULT, type_);
     pump_.reset(new MessagePumpDefault());
   }
 }
 
@@ skipping 567 matching lines @@
       fd,
       persistent,
       mode,
       controller,
       delegate);
 }
 
 #endif
 
 }  // namespace base