Switch ObserverList::size() to ObserverList::might_have_observers() Pt.1

ash/launcher/launcher_button.cc

 // Copyright (c) 2012 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 "ash/launcher/launcher_button.h"
 
 #include <algorithm>
 
 #include "ash/ash_switches.h"
 #include "ash/launcher/launcher_button_host.h"
@@ skipping 49 matching lines @@
     static LauncherButtonAnimation* s_instance = new LauncherButtonAnimation();
     return s_instance;
   }
 
   void AddObserver(Observer* observer) {
     observers_.AddObserver(observer);
   }
 
   void RemoveObserver(Observer* observer) {
     observers_.RemoveObserver(observer);
-    if (observers_.size() == 0)
+    if (!observers_.might_have_observers())
       animation_.Stop();
   }
 
   int GetAlpha() {
     return GetThrobAnimation().CurrentValueBetween(0, 255);
   }
 
   double GetAnimation() {
     return GetThrobAnimation().GetCurrentValue();
   }
@@ skipping 481 matching lines @@
       shelf_layout_manager_->PrimaryAxisValue(views::ImageView::CENTER,
                                               views::ImageView::LEADING));
   icon_view_->SetVerticalAlignment(
       shelf_layout_manager_->PrimaryAxisValue(views::ImageView::LEADING,
                                               views::ImageView::CENTER));
   SchedulePaint();
 }
 
 }  // namespace internal
 }  // namespace ash