[Media Router] Assign each route a current cast mode if possible

chrome/browser/ui/webui/media_router/media_router_ui.h

Index: chrome/browser/ui/webui/media_router/media_router_ui.h
diff --git a/chrome/browser/ui/webui/media_router/media_router_ui.h b/chrome/browser/ui/webui/media_router/media_router_ui.h
index 50804a91e1c7e340a5f2c96ba99c276853cb3abd..3b7a7ae248d86ecb9110947ab0707c20d90aceeb 100644
--- a/chrome/browser/ui/webui/media_router/media_router_ui.h
+++ b/chrome/browser/ui/webui/media_router/media_router_ui.h
@@ -137,6 +137,10 @@ class MediaRouterUI : public ConstrainedWebDialogUI,
     return joinable_route_ids_;
   }
   const std::set<MediaCastMode>& cast_modes() const { return cast_modes_; }
+  const std::unordered_map<MediaRoute::Id, MediaCastMode>& current_cast_modes()
+      const {
+    return current_cast_modes_;
+  }
   const content::WebContents* initiator() const { return initiator_; }
 
   // Marked virtual for tests.
@@ -159,6 +163,12 @@ class MediaRouterUI : public ConstrainedWebDialogUI,
                            UIMediaRoutesObserverFiltersNonDisplayRoutes);
   FRIEND_TEST_ALL_PREFIXES(MediaRouterUITest,
       UIMediaRoutesObserverFiltersNonDisplayJoinableRoutes);
+  FRIEND_TEST_ALL_PREFIXES(MediaRouterUITest,
+      UIMediaRoutesObserverAssignsCurrentCastModes);
+  FRIEND_TEST_ALL_PREFIXES(MediaRouterUITest,
+      UIMediaRoutesObserverSkipsUnavailableCastModes);
+  FRIEND_TEST_ALL_PREFIXES(MediaRouterUITest,
+      UIMediaRoutesObserverFiltersNonDisplayJoinableRoutes);
   FRIEND_TEST_ALL_PREFIXES(MediaRouterUITest, GetExtensionNameExtensionPresent);
   FRIEND_TEST_ALL_PREFIXES(MediaRouterUITest,
                            GetExtensionNameEmptyWhenNotInstalled);
@@ -172,11 +182,17 @@ class MediaRouterUI : public ConstrainedWebDialogUI,
 
   class UIMediaRoutesObserver : public MediaRoutesObserver {
    public:
-    using RoutesUpdatedCallback =
-        base::Callback<void(const std::vector<MediaRoute>&,
-            const std::vector<MediaRoute::Id>&)>;
-    UIMediaRoutesObserver(MediaRouter* router, const MediaSource::Id& source_id,
-                          const RoutesUpdatedCallback& callback);
+    using RoutesUpdatedCallback = base::Callback<void(
+        const std::vector<MediaRoute>&,
+        const std::vector<MediaRoute::Id>&,
+        const std::unordered_map<MediaRoute::Id, MediaCastMode>&)>;
+    using SourceCastModeMapCallback =
+        base::Callback<std::unordered_map<MediaSource::Id, MediaCastMode>()>;
+    UIMediaRoutesObserver(
+        MediaRouter* router,
+        const MediaSource::Id& source_id,
+        const SourceCastModeMapCallback& source_cast_mode_callback,
+        const RoutesUpdatedCallback& callback);
     ~UIMediaRoutesObserver() override;
 
     // MediaRoutesObserver
@@ -185,7 +201,8 @@ class MediaRouterUI : public ConstrainedWebDialogUI,
         const std::vector<MediaRoute::Id>& joinable_route_ids) override;
 
    private:
-    // Callback to the owning MediaRouterUI instance.
+    // Callbacks to the owning MediaRouterUI instance.
+    SourceCastModeMapCallback source_cast_mode_callback_;
     RoutesUpdatedCallback callback_;
 
     DISALLOW_COPY_AND_ASSIGN(UIMediaRoutesObserver);
@@ -203,9 +220,15 @@ class MediaRouterUI : public ConstrainedWebDialogUI,
   // Ignored if the UI is not yet initialized.
   void SetIssue(const Issue* issue);
 
+  // Called by |routes_observer_| to get an updated map from media sources to
+  // their current cast mode.
+  std::unordered_map<MediaSource::Id, MediaCastMode> GetAvailableSourceMap();
+
   // Called by |routes_observer_| when the set of active routes has changed.
   void OnRoutesUpdated(const std::vector<MediaRoute>& routes,
-      const std::vector<MediaRoute::Id>& joinable_route_ids);
+      const std::vector<MediaRoute::Id>& joinable_route_ids,
+      const std::unordered_map<MediaRoute::Id, MediaCastMode>&
+          current_cast_modes);
 
   // Callback passed to MediaRouter to receive response to route creation
   // requests.
@@ -283,6 +306,7 @@ class MediaRouterUI : public ConstrainedWebDialogUI,
   std::vector<MediaRoute> routes_;
   std::vector<MediaRoute::Id> joinable_route_ids_;
   CastModeSet cast_modes_;
+  std::unordered_map<MediaRoute::Id, MediaCastMode> current_cast_modes_;
 
   std::unique_ptr<QueryResultManager> query_result_manager_;