x11: Remove MessagePumpObserver.

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 651 matching lines @@
   static_cast<MessagePumpForUI*>(pump_.get())->Start(this);
 }
 #endif
 
 #if defined(OS_IOS)
 void MessageLoopForUI::Attach() {
   static_cast<MessagePumpUIApplication*>(pump_.get())->Attach(this);
 }
 #endif
 
-#if !defined(OS_NACL) && (defined(TOOLKIT_GTK) || \
-                          defined(OS_WIN) || defined(USE_X11))
+#if !defined(OS_NACL) && defined(OS_WIN)
 void MessageLoopForUI::AddObserver(Observer* observer) {
   pump_ui()->AddObserver(observer);
 }
 
 void MessageLoopForUI::RemoveObserver(Observer* observer) {
   pump_ui()->RemoveObserver(observer);
 }
-#endif  //  !defined(OS_MACOSX) && !defined(OS_NACL) && !defined(OS_ANDROID)
+#endif  // !defined(OS_NACL) && defined(OS_WIN)
 
 #if defined(USE_OZONE)
 bool MessageLoopForUI::WatchFileDescriptor(
     int fd,
     bool persistent,
     MessagePumpLibevent::Mode mode,
     MessagePumpLibevent::FileDescriptorWatcher *controller,
     MessagePumpLibevent::Watcher *delegate) {
   return pump_libevent()->WatchFileDescriptor(
       fd,
@@ skipping 47 matching lines @@
       fd,
       persistent,
       mode,
       controller,
       delegate);
 }
 
 #endif
 
 }  // namespace base