[Reland] Enable AutoResize for Constrained Web Dialogs for Mac.

chrome/browser/ui/cocoa/extensions/extension_install_dialog_controller.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_EXTENSIONS_EXTENSION_INSTALL_DIALOG_CONTROLER_H_
 #define CHROME_BROWSER_UI_COCOA_EXTENSIONS_EXTENSION_INSTALL_DIALOG_CONTROLER_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_nsobject.h"
@@ skipping 39 matching lines @@
   ExtensionInstallViewController* view_controller() const {
     return view_controller_;
   }
 
  private:
   void OnPromptButtonClicked(ExtensionInstallPrompt::Result result,
                              const char* decision_event);
 
   ExtensionInstallPrompt::DoneCallback done_callback_;
   base::scoped_nsobject<ExtensionInstallViewController> view_controller_;
-  scoped_ptr<ConstrainedWindowMac> constrained_window_;
+  std::unique_ptr<ConstrainedWindowMac> constrained_window_;
   scoped_ptr<extensions::ExperienceSamplingEvent> sampling_event_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionInstallDialogController);
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_EXTENSIONS_EXTENSION_INSTALL_DIALOG_CONTROLLER_H_