Add a NavigationThrottle to the public content/ interface

content/browser/frame_host/navigator_delegate.cc

 // Copyright 2014 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 "content/browser/frame_host/navigator_delegate.h"
 
 namespace content {
 
+std::vector<NavigationThrottle*> NavigatorDelegate::AddNavigationThrottles(
+    NavigationHandle* navigation_handle) {
+  return std::vector<NavigationThrottle*>();
+}
+
 bool NavigatorDelegate::CanOverscrollContent() const {
   return false;
 }
 
 bool NavigatorDelegate::ShouldPreserveAbortedURLs() {
   return false;
 }
 
 }  // namespace content