Non-Local Join for Media Router and Presentation API

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

Index: chrome/browser/ui/webui/media_router/media_router_ui.cc
diff --git a/chrome/browser/ui/webui/media_router/media_router_ui.cc b/chrome/browser/ui/webui/media_router/media_router_ui.cc
index 4d05a519aebd76df1736f5ceaba1458dc1516142..f4fab98eab9a8bacbb43f4cf6d4ab1c6401a8e18 100644
--- a/chrome/browser/ui/webui/media_router/media_router_ui.cc
+++ b/chrome/browser/ui/webui/media_router/media_router_ui.cc
@@ -334,6 +334,57 @@ bool MediaRouterUI::CreateRoute(const MediaSink::Id& sink_id,
   return true;
 }
 
+bool MediaRouterUI::JoinRoute(const MediaSink::Id& sink_id,
+                              const MediaRoute::Id& route_id) {
+  DCHECK(query_result_manager_.get());
+  DCHECK(initiator_);
+
+  current_route_request_id_ = ++route_request_counter_;
+  GURL origin = frame_url_.GetOrigin();
+
+  MediaSource source =
+      query_result_manager_->GetSourceForCastMode(MediaCastMode::DEFAULT);
+
+  if (source.Empty()) {
+    LOG(ERROR) << "No MediaSource to join";
+    return false;
+  }
+
+  DCHECK(origin.is_valid());
+
+  // There are 3 cases. In all cases the MediaRouterUI will need to be notified.

[mark a. foltz, 2015/11/09 19:12:31]

This comment block needs to be rewritten to discuss the join case.

+  // (1) Non-presentation route request (e.g., mirroring). No additional
+  // notification necessary.
+  // (2) Presentation route request for a Presentation API startSession call.
+  // The startSession (CreatePresentationSessionRequest) will need to be
+  // answered with the
+  // route response.
+  // (3) Browser-initiated presentation route request. If successful,
+  // PresentationServiceDelegateImpl will have to be notified. Note that we
+  // treat subsequent route requests from a Presentation API-initiated dialogs
+  // as browser-initiated.
+  std::vector<MediaRouteResponseCallback> route_response_callbacks;
+  route_response_callbacks.push_back(base::Bind(
+      &MediaRouterUI::OnRouteResponseReceived, weak_factory_.GetWeakPtr(),
+      current_route_request_id_, sink_id));
+
+  if (presentation_service_delegate_) {
+    route_response_callbacks.push_back(
+        base::Bind(&PresentationServiceDelegateImpl::OnRouteResponse,
+                   presentation_service_delegate_));
+  }
+
+  // Start the timer.
+  route_creation_timer_.Start(
+      FROM_HERE, base::TimeDelta::FromSeconds(kCreateRouteTimeoutSeconds), this,
+      &MediaRouterUI::RouteCreationTimeout);
+  std::string presentation_id("non-local-join_");

[mark a. foltz, 2015/11/09 19:12:31]

I don't think the UI should be manufacturing presentation ids.  imcheng@ do you
have a suggestion on where this logic should live?

[matt.boetger, 2015/11/09 19:24:35]

If the router is to create the presentation Id, I might have to change the media
router interface to have a different, 'non-local' join functionality because the
auto-join route method would break if I move the creation into the JoinRoute
method.  

[imcheng, 2015/11/09 22:23:15]

I can see 2 ways to make that work:
1) Add a JoinRouteByRouteId method in MediaRouter that takes a MediaRoute::Id
instead of presentation id. MediaRouterMojImpl / MediaRouterAndroid will then
generate the presentation id with a special prefix ("mr_joinByRouteId_") and
call to MRPM with the special presentation id. The MRPs will have to respect the
pres id.

2. Or we can be more explicit and add the JoinRouteByRouteId method to both
MediaRouter and MRPM.


I prefer #2 as it is more explicit and avoids the use of hacks. The
JoinRouteByRouteId MRP implementation should not be too complicated either.

+  presentation_id += route_id;

[mark a. foltz, 2015/11/09 19:12:31]

What if there are simultaneous requests to join the same route?

+  router_->JoinRoute(source.id(), presentation_id, origin,
+                     initiator_, route_response_callbacks);
+  return true;
+}
+
 void MediaRouterUI::CloseRoute(const MediaRoute::Id& route_id) {
   router_->CloseRoute(route_id);
 }