Reland the patch to fix the problem that sometimes panel on Windows is not set to top-most.

chrome/browser/ui/panels/panel_browser_view.cc

 // Copyright (c) 2011 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 "chrome/browser/ui/panels/panel_browser_view.h"
 
 #include "base/logging.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/panels/panel_browser_frame_view.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
@@ skipping 36 matching lines @@
     is_drawing_attention_(false),
     old_focused_view_(NULL) {
 }
 
 PanelBrowserView::~PanelBrowserView() {
 }
 
 void PanelBrowserView::Init() {
   BrowserView::Init();
 
-  GetWidget()->SetAlwaysOnTop(true);
   GetWidget()->non_client_view()->SetAccessibleName(
       l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
 }
 
 void PanelBrowserView::Close() {
   GetWidget()->RemoveObserver(this);
   closed_ = true;
 
   // Cancel any currently running animation since we're closing down.
   if (bounds_animator_.get())
@@ skipping 393 matching lines @@
       panel_browser_view_->mouse_pressed_point_.y() + delta_y));
 }
 
 void NativePanelTestingWin::CancelDragTitlebar() {
   panel_browser_view_->OnTitlebarMouseCaptureLost();
 }
 
 void NativePanelTestingWin::FinishDragTitlebar() {
   panel_browser_view_->OnTitlebarMouseReleased();
 }