CustomButton: restrict animation repaints to buttons that actually animate

chrome/browser/ui/views/tabs/tab_strip.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 "chrome/browser/ui/views/tabs/tab_strip.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <iterator>
@@ skipping 304 matching lines @@
   // were we destroyed?
   bool* destroyed_;
 
   DISALLOW_COPY_AND_ASSIGN(NewTabButton);
 };
 
 NewTabButton::NewTabButton(TabStrip* tab_strip, views::ButtonListener* listener)
     : views::ImageButton(listener),
       tab_strip_(tab_strip),
       destroyed_(NULL) {
+  set_animate_on_state_change(true);
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   set_triggerable_event_flags(triggerable_event_flags() |
                               ui::EF_MIDDLE_MOUSE_BUTTON);
 #endif
 }
 
 NewTabButton::~NewTabButton() {
   if (destroyed_)
     *destroyed_ = true;
 }
@@ skipping 2466 matching lines @@
           ConvertPointToViewAndGetEventHandler(this, newtab_button_, point);
       if (view)
         return view;
     }
     Tab* tab = FindTabForEvent(point);
     if (tab)
       return ConvertPointToViewAndGetEventHandler(this, tab, point);
   }
   return this;
 }