Promotes Add/RemoveObserver to MessageLoop for linux. Because...

base/message_loop.cc

 // Copyright (c) 2009 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.h"
 
 #include <algorithm>
 
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
@@ skipping 547 matching lines @@
   // A few events we handle (kindred to messages), and used to profile actions.
   VALUE_TO_NUMBER_AND_NAME(kTaskRunEvent)
   VALUE_TO_NUMBER_AND_NAME(kTimerEvent)
 
   {-1, NULL}  // The list must be null terminated, per API to histogram.
 };
 
 //------------------------------------------------------------------------------
 // MessageLoopForUI
 
+#if defined(OS_LINUX) || defined(OS_WIN)
+
+void MessageLoopForUI::AddObserver(Observer* observer) {
+  pump_ui()->AddObserver(observer);
+}
+
+void MessageLoopForUI::RemoveObserver(Observer* observer) {
+  pump_ui()->RemoveObserver(observer);
+}
+
+#endif
+
 #if defined(OS_WIN)
 
 void MessageLoopForUI::Run(Dispatcher* dispatcher) {
   AutoRunState save_state(this);
   state_->dispatcher = dispatcher;
   RunHandler();
 }
 
-void MessageLoopForUI::AddObserver(Observer* observer) {
-  pump_win()->AddObserver(observer);
-}
-
-void MessageLoopForUI::RemoveObserver(Observer* observer) {
-  pump_win()->RemoveObserver(observer);
-}
-
 void MessageLoopForUI::WillProcessMessage(const MSG& message) {
   pump_win()->WillProcessMessage(message);
 }
 void MessageLoopForUI::DidProcessMessage(const MSG& message) {
   pump_win()->DidProcessMessage(message);
 }
 void MessageLoopForUI::PumpOutPendingPaintMessages() {
   pump_ui()->PumpOutPendingPaintMessages();
 }
 
@@ skipping 21 matching lines @@
                                            Watcher *delegate) {
   return pump_libevent()->WatchFileDescriptor(
       fd,
       persistent,
       static_cast<base::MessagePumpLibevent::Mode>(mode),
       controller,
       delegate);
 }
 
 #endif