app_list: Fix shadow bleeds over launcher button and steals mouse events

ui/views/widget/widget_delegate.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/widget_delegate.h"
 
 #include "base/utf_string_conversions.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/views/bubble/bubble_delegate.h"
 #include "ui/views/view.h"
@@ skipping 124 matching lines @@
 }
 
 NonClientFrameView* WidgetDelegate::CreateNonClientFrameView(Widget* widget) {
   return NULL;
 }
 
 bool WidgetDelegate::WillProcessWorkAreaChange() const {
   return false;
 }
 
+bool WidgetDelegate::HasHitTestMask() const {
+  return false;
+}
+
+void WidgetDelegate::GetHitTestMask(gfx::Path* mask) const {
+  DCHECK(mask);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // WidgetDelegateView:
 
 WidgetDelegateView::WidgetDelegateView() {
 }
 
 WidgetDelegateView::~WidgetDelegateView() {
 }
 
 Widget* WidgetDelegateView::GetWidget() {
   return View::GetWidget();
 }
 
 const Widget* WidgetDelegateView::GetWidget() const {
   return View::GetWidget();
 }
 
 }  // namespace views