A number of paint optimizations to improve overall paint times.

ui/views/widget/desktop_aura/desktop_root_window_host_win.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 "ui/views/widget/desktop_aura/desktop_root_window_host_win.h"
 
 #include "base/win/metro.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/aura/client/aura_constants.h"
@@ skipping 327 matching lines @@
   SetWindowTransparency();
 }
 
 bool DesktopRootWindowHostWin::IsFullscreen() const {
   return message_handler_->fullscreen_handler()->fullscreen();
 }
 
 void DesktopRootWindowHostWin::SetOpacity(unsigned char opacity) {
   message_handler_->SetOpacity(static_cast<BYTE>(opacity));
   content_window_->layer()->SetOpacity(opacity / 255.0);
-  GetWidget()->GetRootView()->SchedulePaint();
 }
 
 void DesktopRootWindowHostWin::SetWindowIcons(
     const gfx::ImageSkia& window_icon, const gfx::ImageSkia& app_icon) {
   message_handler_->SetWindowIcons(window_icon, app_icon);
 }
 
 void DesktopRootWindowHostWin::InitModalType(ui::ModalType modal_type) {
   message_handler_->InitModalType(modal_type);
 }
@@ skipping 555 matching lines @@
 
 // static
 DesktopRootWindowHost* DesktopRootWindowHost::Create(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura) {
   return new DesktopRootWindowHostWin(native_widget_delegate,
                                       desktop_native_widget_aura);
 }
 
 }  // namespace views