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

chrome/browser/ui/webui/constrained_web_dialog_ui.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_WEBUI_CONSTRAINED_WEB_DIALOG_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_CONSTRAINED_WEB_DIALOG_UI_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "content/public/browser/web_ui_controller.h"
@@ skipping 33 matching lines @@
 
   // Returns the native type used to display the dialog.
   virtual gfx::NativeWindow GetNativeDialog() = 0;
 
   // Returns the minimum size for the dialog.
   virtual gfx::Size GetMinimumSize() const = 0;
 
   // Returns the maximum size for the dialog.
   virtual gfx::Size GetMaximumSize() const = 0;
 
+  // Returns the preferred size for the dialog, or an empty size if
+  // the dialog has been closed.
   virtual gfx::Size GetPreferredSize() const = 0;
 
  protected:
   virtual ~ConstrainedWebDialogDelegate() {}
 };
 
 // ConstrainedWebDialogUI is a facility to show HTML WebUI content
 // in a tab-modal constrained dialog.  It is implemented as an adapter
 // between an WebDialogUI object and a web contents modal dialog.
 //
@@ skipping 44 matching lines @@
 // |min_size| is the minimum size of the dialog.
 // |max_size| is the maximum size of the dialog.
 ConstrainedWebDialogDelegate* ShowConstrainedWebDialogWithAutoResize(
     content::BrowserContext* browser_context,
     ui::WebDialogDelegate* delegate,
     content::WebContents* overshadowed,
     const gfx::Size& min_size,
     const gfx::Size& max_size);
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CONSTRAINED_WEB_DIALOG_UI_H_