Remove unnecessary function ChromeExtensionChooserDialog::web_contents()

chrome/browser/ui/cocoa/extensions/chooser_dialog_cocoa.mm

 // Copyright 2016 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.
 
 #import "chrome/browser/ui/cocoa/extensions/chooser_dialog_cocoa.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 47 matching lines @@
 }
 
 void ChooserDialogCocoa::Dismissed() {
   if (constrained_window_)
     constrained_window_->CloseWebContentsModalDialog();
 }
 
 void ChromeExtensionChooserDialog::ShowDialog(
     ChooserController* chooser_controller) const {
   web_modal::WebContentsModalDialogManager* manager =
-      web_modal::WebContentsModalDialogManager::FromWebContents(web_contents());
+      web_modal::WebContentsModalDialogManager::FromWebContents(web_contents_);
   if (manager) {
     // These objects will delete themselves when the dialog closes.
     ChooserDialogCocoa* chooser_dialog =
-        new ChooserDialogCocoa(web_contents(), chooser_controller);
+        new ChooserDialogCocoa(web_contents_, chooser_controller);
     chooser_dialog->ShowDialog();
   }
 }