aura: No shadow for transparent window.

ash/tooltips/tooltip_controller.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/tooltips/tooltip_controller.h"
 
 #include <vector>
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
@@ skipping 95 matching lines @@
 
 // Creates a widget of type TYPE_TOOLTIP
 views::Widget* CreateTooltip() {
   views::Widget* widget = new views::Widget;
   views::Widget::InitParams params;
   // For aura, since we set the type to TOOLTIP_TYPE, the widget will get
   // auto-parented to the MenuAndTooltipsContainer.
   params.type = views::Widget::InitParams::TYPE_TOOLTIP;
   params.keep_on_top = true;
   params.accept_events = false;
-  params.transparent = true;
   params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   widget->Init(params);
   return widget;
 }
 
 }  // namespace
 
 namespace ash {
 namespace internal {
 
@@ skipping 195 matching lines @@
     }
   }
 }
 
 bool TooltipController::IsTooltipVisible() {
   return tooltip_->IsVisible();
 }
 
 }  // namespace internal
 }  // namespace ash