Add app.window.alphaEnabled() and onAlphaEnabledChanged.

ui/views/widget/widget_unittest.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 <algorithm>
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 636 matching lines @@
     widget->IsMouseEventsEnabled();
     widget->SetNativeWindowProperty("xx", widget);
     widget->GetNativeWindowProperty("xx");
     widget->GetFocusTraversable();
     widget->GetLayer();
     widget->ReorderNativeViews();
     widget->SetCapture(widget->GetRootView());
     widget->ReleaseCapture();
     widget->HasCapture();
     widget->GetWorkAreaBoundsInScreen();
+    widget->IsTranslucentWindowOpacitySupported();
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WidgetWithDestroyedNativeViewTest);
 };
 
 TEST_F(WidgetWithDestroyedNativeViewTest, Test) {
   {
     Widget widget;
     Widget::InitParams params = CreateParams(Widget::InitParams::TYPE_POPUP);
@@ skipping 1924 matching lines @@
   EXPECT_EQ(3, view->GetEventCount(ui::ET_MOUSE_PRESSED));
   EXPECT_EQ(3, view->GetEventCount(ui::ET_MOUSE_RELEASED));
   EXPECT_EQ(1, view->GetEventCount(ui::ET_MOUSE_DRAGGED));
   EXPECT_EQ(ui::EF_LEFT_MOUSE_BUTTON, view->last_flags());
 
   widget->CloseNow();
 }
 
 }  // namespace test
 }  // namespace views