[Media Router] Implement an internal Media Routes observer.

chrome/browser/media/router/route_request_result.h

 // 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.
 
 #ifndef CHROME_BROWSER_MEDIA_ROUTER_ROUTE_REQUEST_RESULT_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_ROUTE_REQUEST_RESULT_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 16 matching lines @@
 // |route|: nullptr
 // |presentation_id|: Empty string.
 // |error|: Non-empty string describing the error.
 // |result_code|: A value from RouteRequestResult describing the error.
 class RouteRequestResult {
  public:
   enum ResultCode {
     UNKNOWN_ERROR,
     OK,
     TIMED_OUT,
+    ROUTE_NOT_FOUND,
     INVALID_ORIGIN,
     OFF_THE_RECORD_MISMATCH
   };
 
   static std::unique_ptr<RouteRequestResult> FromSuccess(
       std::unique_ptr<MediaRoute> route,
       const std::string& presentation_id);
   static std::unique_ptr<RouteRequestResult> FromError(const std::string& error,
                                                        ResultCode result_code);
 
@@ skipping 16 matching lines @@
   std::string presentation_id_;
   std::string error_;
   ResultCode result_code_;
 
   DISALLOW_COPY_AND_ASSIGN(RouteRequestResult);
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_ROUTE_REQUEST_RESULT_H_