status_icons: Factor out status icon observer into its own header file.

chrome/browser/status_icons/status_icon.cc

 // Copyright (c) 2011 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 "chrome/browser/status_icons/status_icon.h"
 
+#include "chrome/browser/status_icons/status_icon_observer.h"
 #include "ui/base/models/menu_model.h"
 
 StatusIcon::StatusIcon() {
 }
 
 StatusIcon::~StatusIcon() {
 }
 
-void StatusIcon::AddObserver(Observer* observer) {
+void StatusIcon::AddObserver(StatusIconObserver* observer) {
   observers_.AddObserver(observer);
 }
 
-void StatusIcon::RemoveObserver(Observer* observer) {
+void StatusIcon::RemoveObserver(StatusIconObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
-bool StatusIcon::HasObservers() {
+bool StatusIcon::HasObservers() const {
   return observers_.size() > 0;
 }
 
 void StatusIcon::DispatchClickEvent() {
-  FOR_EACH_OBSERVER(Observer, observers_, OnClicked());
+  FOR_EACH_OBSERVER(StatusIconObserver, observers_, OnStatusIconClicked());
 }
 
 void StatusIcon::SetContextMenu(ui::MenuModel* menu) {
   context_menu_contents_.reset(menu);
   UpdatePlatformContextMenu(menu);
 }