[MediaRouter] Update JoinRoute behavior to allow non-local routes.

chrome/browser/media/router/media_router_base.cc

Index: chrome/browser/media/router/media_router_base.cc
diff --git a/chrome/browser/media/router/media_router_base.cc b/chrome/browser/media/router/media_router_base.cc
index 36e092ea0c0c39cab4ec080ead7a9fd63bb657d3..668e78ff42aff70df6488b556a8417463abc0b38 100644
--- a/chrome/browser/media/router/media_router_base.cc
+++ b/chrome/browser/media/router/media_router_base.cc
@@ -19,7 +19,7 @@ class MediaRouterBase::InternalMediaRoutesObserver
     : public MediaRoutesObserver {
  public:
   explicit InternalMediaRoutesObserver(MediaRouter* router)
-      : MediaRoutesObserver(router), has_local_route(false) {}
+      : MediaRoutesObserver(router), has_route(false) {}
   ~InternalMediaRoutesObserver() override {}
 
   // MediaRoutesObserver
@@ -27,15 +27,14 @@ class MediaRouterBase::InternalMediaRoutesObserver
       const std::vector<MediaRoute>& routes,
       const std::vector<MediaRoute::Id>& joinable_route_ids) override {
     off_the_record_route_ids.clear();
-    has_local_route = false;
+    has_route = !routes.empty();

[imcheng, 2016/05/12 00:22:20]

nit: add a TODO here to optimize this to only check for joinable routexs.

As a side note, I wonder if |joinable_route_ids| can be reused for this purpose.
Currently, if there is no MediaSource associated with a routes query, we return
an empty joinable route id list. Perhaps that could be changed to return routes
that are joinable via any means, but I will have go back and check if it will
break the UI.

[mark a. foltz, 2016/05/12 18:38:43]

Done.
Filed crbug.com/611486 and added to TODO.

     for (const auto& route : routes) {
-      has_local_route |= route.is_local();
       if (route.off_the_record())
         off_the_record_route_ids.push_back(route.media_route_id());
     }
   }
 
-  bool has_local_route;
+  bool has_route;
   std::vector<MediaRoute::Id> off_the_record_route_ids;
 
  private:
@@ -103,8 +102,8 @@ void MediaRouterBase::NotifyPresentationConnectionClose(
   callbacks->Notify(info);
 }
 
-bool MediaRouterBase::HasLocalRoute() const {
-  return internal_routes_observer_->has_local_route;
+bool MediaRouterBase::HasJoinableRoute() const {
+  return internal_routes_observer_->has_route;
 }
 
 void MediaRouterBase::Initialize() {