Teach navigation throttles how to cancel requests in WillProcessResponse.

content/public/browser/navigation_throttle.cc

 // Copyright 2015 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/public/browser/navigation_throttle.h"
 
 namespace content {
 
 NavigationThrottle::NavigationThrottle(NavigationHandle* navigation_handle)
     : navigation_handle_(navigation_handle) {}
 
 NavigationThrottle::~NavigationThrottle() {}
 
 NavigationThrottle::ThrottleCheckResult NavigationThrottle::WillStartRequest() {
   return NavigationThrottle::PROCEED;
 }
 
 NavigationThrottle::ThrottleCheckResult
 NavigationThrottle::WillRedirectRequest() {
   return NavigationThrottle::PROCEED;
 }
 
+NavigationThrottle::ThrottleCheckResult
+NavigationThrottle::WillProcessResponse() {
+  return NavigationThrottle::PROCEED;
+}
+
 }  // namespace content