[Media Router] Add a presentation id to MediaRoute mapping in the MR

chrome/browser/media/router/media_route.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_MEDIA_ROUTE_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTE_H_
 
 #include <string>
 
 #include "base/containers/small_map.h"
@@ skipping 73 matching lines @@
   bool for_display() const { return for_display_; }
 
   void set_incognito(bool is_incognito) { is_incognito_ = is_incognito; }
   bool is_incognito() const { return is_incognito_; }
 
   void set_offscreen_presentation(bool is_offscreen_presentation) {
     is_offscreen_presentation_ = is_offscreen_presentation;
   }
   bool is_offscreen_presentation() const { return is_offscreen_presentation_; }
 
+  void set_presentation_id(const std::string& presentation_id) {
+    presentation_id_ = presentation_id;
+  }
+  const base::Optional<std::string>& presentation_id() const {
+    return presentation_id_;
+  }
+
   bool Equals(const MediaRoute& other) const;
 
  private:
   // The media route identifier.
   MediaRoute::Id media_route_id_;
 
   // The media source being routed.
   MediaSource media_source_;
 
   // The ID of sink being routed to.
@@ skipping 14 matching lines @@
 
   // |true| if the route can be displayed in the UI.
   bool for_display_ = false;
 
   // |true| if the route was created by an incognito profile.
   bool is_incognito_ = false;
 
   // |true| if the presentation associated with this route is an offscreen
   // presentation.
   bool is_offscreen_presentation_ = false;
+
+  // Presentation id associated with this media route object.
+  base::Optional<std::string> presentation_id_;
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTE_H_