app_list: Touch scroll and animation improvement.

ui/app_list/app_list_view.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/app_list/app_list_view.h"
 
 #include "base/string_util.h"
 #include "ui/app_list/app_list_bubble_border.h"
 #include "ui/app_list/app_list_item_view.h"
 #include "ui/app_list/app_list_model.h"
@@ skipping 66 matching lines @@
   views::BubbleDelegateView::CreateBubble(this);
 
   // Overrides border with AppListBubbleBorder.
   bubble_border_ = new AppListBubbleBorder(this, search_box_view_);
   GetBubbleFrameView()->SetBubbleBorder(bubble_border_);
   SetBubbleArrowLocation(arrow_location);
 
   // Resets default background since AppListBubbleBorder paints background.
   GetBubbleFrameView()->set_background(NULL);
 
+  contents_view_->SetPaintToLayer(true);
+  contents_view_->SetFillsBoundsOpaquely(false);
+  contents_view_->layer()->SetMasksToBounds(true);
+
   CreateModel();
 }
 
 void AppListView::SetBubbleArrowLocation(
     views::BubbleBorder::ArrowLocation arrow_location) {
   DCHECK(bubble_border_);
   bubble_border_->set_arrow_location(arrow_location);
   SizeToContents();  // Recalcuates with new border.
 }
 
@@ skipping 97 matching lines @@
 }
 
 void AppListView::InvokeResultAction(const SearchResult& result,
                                      int action_index,
                                      int event_flags) {
   if (delegate_.get())
     delegate_->InvokeSearchResultAction(result, action_index, event_flags);
 }
 
 }  // namespace app_list