Close web contents modal dialogs on content load start

chrome/browser/ui/cocoa/constrained_window/constrained_window_mac.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_COCOA_CONSTRAINED_WINDOW_CONSTRAINED_WINDOW_MAC_
 #define CHROME_BROWSER_UI_COCOA_CONSTRAINED_WINDOW_CONSTRAINED_WINDOW_MAC_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_nsobject.h"
@@ skipping 23 matching lines @@
       id<ConstrainedWindowSheet> sheet);
   virtual ~ConstrainedWindowMac();
 
   void ShowWebContentsModalDialog();
   // Closes the constrained window and deletes this instance.
   void CloseWebContentsModalDialog();
   void FocusWebContentsModalDialog();
   void PulseWebContentsModalDialog();
   web_modal::NativeWebContentsModalDialog GetNativeDialog();
 
+  void SetPreventCloseOnLoadStart(bool prevent);
+
  private:
   // Gets the parent window of the dialog.
   NSWindow* GetParentWindow() const;
 
   ConstrainedWindowMacDelegate* delegate_;  // weak, owns us.
 
   // The WebContents that owns and constrains this ConstrainedWindowMac. Weak.
   content::WebContents* web_contents_;
 
   base::scoped_nsprotocol<id<ConstrainedWindowSheet>> sheet_;
 
   // This is true if the constrained window has been shown.
   bool shown_;
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_CONSTRAINED_WINDOW_CONSTRAINED_WINDOW_MAC_