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

chrome/browser/ui/cocoa/autofill/autofill_dialog_cocoa.mm

 // Copyright (c) 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.
 
 #include "chrome/browser/ui/cocoa/autofill/autofill_dialog_cocoa.h"
 
 #include "base/bind.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 20 matching lines @@
 
 void AutofillDialogCocoa::Show() {
   // This should only be called once.
   DCHECK(!sheet_delegate_.get());
   sheet_delegate_.reset([[AutofillDialogWindowController alloc]
        initWithWebContents:delegate_->GetWebContents()
                     dialog:this]);
   base::scoped_nsobject<CustomConstrainedWindowSheet> sheet(
       [[CustomConstrainedWindowSheet alloc]
           initWithCustomWindow:[sheet_delegate_ window]]);
-  constrained_window_.reset(
-      new ConstrainedWindowMac(this, delegate_->GetWebContents(), sheet));
+  constrained_window_ =
+      CreateAndShowWebModalDialogMac(this, delegate_->GetWebContents(), sheet);
   [sheet_delegate_ show];
 }
 
 void AutofillDialogCocoa::Hide() {
   [sheet_delegate_ hide];
 }
 
 void AutofillDialogCocoa::PerformClose() {
   if (!close_weak_ptr_factory_.HasWeakPtrs()) {
     base::MessageLoop::current()->PostTask(
@@ skipping 62 matching lines @@
 }
 
 void AutofillDialogCocoa::OnConstrainedWindowClosed(
     ConstrainedWindowMac* window) {
   constrained_window_.reset();
   // |this| belongs to |delegate_|, so no self-destruction here.
   delegate_->ViewClosed();
 }
 
 }  // autofill