Support dragging panels to stack and snap.

chrome/browser/ui/cocoa/panels/panel_cocoa.mm

 // 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 "chrome/browser/ui/cocoa/panels/panel_cocoa.h"
 
 #include "base/logging.h"
 #import "chrome/browser/ui/cocoa/chrome_event_processing_window.h"
 #import "chrome/browser/ui/cocoa/panels/panel_titlebar_view_cocoa.h"
 #import "chrome/browser/ui/cocoa/panels/panel_utils_cocoa.h"
@@ skipping 219 matching lines @@
 }
 
 void PanelCocoa::EnableResizeByMouse(bool enable) {
   [controller_ enableResizeByMouse:enable];
 }
 
 void PanelCocoa::UpdatePanelMinimizeRestoreButtonVisibility() {
   [controller_ updateTitleBarMinimizeRestoreButtonVisibility];
 }
 
+void PanelCocoa::UpdatePanelStackingProperty() {
+  NOTIMPLEMENTED();
+}
+
 void PanelCocoa::PanelExpansionStateChanging(
     Panel::ExpansionState old_state, Panel::ExpansionState new_state) {
   [controller_ updateWindowLevel:(new_state != Panel::EXPANDED)];
 }
 
 void PanelCocoa::AttachWebContents(content::WebContents* contents) {
   [controller_ webContentsInserted:contents];
 }
 
 void PanelCocoa::DetachWebContents(content::WebContents* contents) {
@@ skipping 132 matching lines @@
       return ![[titlebar() closeButton] isHidden];
     case panel::MINIMIZE_BUTTON:
       return ![[titlebar() minimizeButton] isHidden];
     case panel::RESTORE_BUTTON:
       return ![[titlebar() restoreButton] isHidden];
     default:
       NOTREACHED();
   }
   return false;
 }