[Media Router] Consistently refer to issue's learn more help page by ID.

chrome/browser/media/router/test_helper.h

 // 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.
 
 #ifndef CHROME_BROWSER_MEDIA_ROUTER_TEST_HELPER_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_TEST_HELPER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 49 matching lines @@
 
   if (arg.route_id() != other.route_id())
     return false;
 
   if (arg.severity() != other.severity())
     return false;
 
   if (arg.is_blocking() != other.is_blocking())
     return false;
 
-  if (arg.help_url() != other.help_url())
+  if (arg.help_page_id() != other.help_page_id())
     return false;
 
   return true;
 }
 
 MATCHER_P(IssueTitleEquals, title, "") {
   return arg.title() == title;
 }
 
 MATCHER_P(StateChageInfoEquals, other, "") {
@@ skipping 33 matching lines @@
  public:
   MockPresentationConnectionStateChangedCallback();
   ~MockPresentationConnectionStateChangedCallback();
   MOCK_METHOD1(Run,
                void(const content::PresentationConnectionStateChangeInfo&));
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_TEST_HELPER_H_