Fix crash when user closes window prior to the "Confirm Install" prompt showing

chrome/browser/ui/cocoa/extensions/windowed_install_dialog_controller.h

 // Copyright 2013 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_EXTENSIONS_WINDOWED_INSTALL_DIALOG_CONTROLLER_H_
 #define CHROME_BROWSER_UI_COCOA_EXTENSIONS_WINDOWED_INSTALL_DIALOG_CONTROLLER_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/gtest_prod_util.h"
 #include "base/mac/scoped_nsobject.h"
 #include "chrome/browser/extensions/extension_install_prompt.h"
 
+class ExtensionInstallPromptShowParams;
 @class ExtensionInstallViewController;
 @class WindowedInstallController;
 
 // Displays an app or extension install or permissions prompt as a standalone
 // NSPanel.
 class WindowedInstallDialogController
     : public ExtensionInstallPrompt::Delegate {
  public:
   // Initializes the ExtensionInstallViewController and shows the window. This
   // object will delete itself when the window is closed.
   WindowedInstallDialogController(
-      const ExtensionInstallPrompt::ShowParams& show_params,
+      ExtensionInstallPromptShowParams* show_params,
       ExtensionInstallPrompt::Delegate* delegate,
       scoped_refptr<ExtensionInstallPrompt::Prompt> prompt);
   ~WindowedInstallDialogController() override;
 
   // Invoked by the -[NSWindow windowWillClose:] notification after a dialog
   // choice is invoked. Releases owned resources, then deletes |this|.
   void OnWindowClosing();
 
   // ExtensionInstallPrompt::Delegate:
   void InstallUIProceed() override;
   void InstallUIAbort(bool user_initiated) override;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(WindowedInstallDialogControllerBrowserTest,
                            ShowInstallDialog);
   ExtensionInstallViewController* GetViewController();
 
   ExtensionInstallPrompt::Delegate* delegate_;
   base::scoped_nsobject<WindowedInstallController> install_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowedInstallDialogController);
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_EXTENSIONS_WINDOWED_INSTALL_DIALOG_CONTROLLER_H_