Enable AutoResize for Constrained Web Dialogs for Mac.

chrome/browser/ui/webui/constrained_web_dialog_delegate_base.h

Index: chrome/browser/ui/webui/constrained_web_dialog_delegate_base.h
diff --git a/chrome/browser/ui/webui/constrained_web_dialog_delegate_base.h b/chrome/browser/ui/webui/constrained_web_dialog_delegate_base.h
index 973608f62e994641f94e13ae4262acd0248ab5b1..2fac4b56b56632492482852bd0da6c365c47fc16 100644
--- a/chrome/browser/ui/webui/constrained_web_dialog_delegate_base.h
+++ b/chrome/browser/ui/webui/constrained_web_dialog_delegate_base.h
@@ -23,6 +23,8 @@ class ConstrainedWebDialogDelegateBase
     : public ConstrainedWebDialogDelegate,
       public ui::WebDialogWebContentsDelegate {
  public:
+  // |browser_context| and |delegate| must outlive |this| instance, whereas
+  // |this| will take ownership of |tab_delegate|.
   ConstrainedWebDialogDelegateBase(content::BrowserContext* browser_context,
                                    ui::WebDialogDelegate* delegate,
                                    WebDialogWebContentsDelegate* tab_delegate);
@@ -46,6 +48,9 @@ class ConstrainedWebDialogDelegateBase
       content::WebContents* source,
       const content::NativeWebKeyboardEvent& event) override;
 
+  // Resize the dialog to the given size.
+  virtual void ResizeToGivenSize(const gfx::Size size);
+
  private:
   scoped_ptr<ui::WebDialogDelegate> web_dialog_delegate_;