Revert 222470 "Use an X event loop in the GPU process on Linux." This is to

trunk/src/base/message_loop/message_loop.h

Index: trunk/src/base/message_loop/message_loop.h
===================================================================
--- trunk/src/base/message_loop/message_loop.h	(revision 222588)
+++ trunk/src/base/message_loop/message_loop.h	(working copy)
@@ -42,10 +42,7 @@
 #else
 #define USE_GTK_MESSAGE_PUMP
 #include "base/message_loop/message_pump_gtk.h"
-#if defined(TOOLKIT_GTK)
-#include "base/message_loop/message_pump_x11.h"
 #endif
-#endif
 
 #endif
 #endif
@@ -113,11 +110,6 @@
   //   This type of ML also supports native UI events (e.g., Windows messages).
   //   See also MessageLoopForUI.
   //
-  // TYPE_GPU
-  //   This type of ML also supports native UI events for use in the GPU
-  //   process. On Linux this will always be an X11 ML (as compared with the
-  //   sometimes-GTK ML in the browser process).
-  //
   // TYPE_IO
   //   This type of ML also supports asynchronous IO.  See also
   //   MessageLoopForIO.
@@ -131,9 +123,6 @@
   enum Type {
     TYPE_DEFAULT,
     TYPE_UI,
-#if defined(TOOLKIT_GTK)
-    TYPE_GPU,
-#endif
     TYPE_IO,
 #if defined(OS_ANDROID)
     TYPE_JAVA,
@@ -427,14 +416,7 @@
   MessagePumpLibevent* pump_libevent() {
     return static_cast<MessagePumpLibevent*>(pump_.get());
   }
-#if defined(TOOLKIT_GTK)
-  friend class MessagePumpX11;
-  MessagePumpX11* pump_gpu() {
-    DCHECK_EQ(TYPE_GPU, type());
-    return static_cast<MessagePumpX11*>(pump_.get());
-  }
 #endif
-#endif
 
   scoped_ptr<MessagePump> pump_;
 
@@ -617,7 +599,7 @@
 #endif
 
  protected:
-#if defined(USE_X11)
+#if defined(USE_AURA) && defined(USE_X11) && !defined(OS_NACL)
   friend class MessagePumpX11;
 #endif
 #if defined(USE_OZONE) && !defined(OS_NACL)