Non-Local Join for Media Router and Presentation API

chrome/browser/media/android/router/media_router_android.cc

Index: chrome/browser/media/android/router/media_router_android.cc
diff --git a/chrome/browser/media/android/router/media_router_android.cc b/chrome/browser/media/android/router/media_router_android.cc
index 614d4d9ec7aa1c988a527856dadcfe0bd18eb3ce..f27e23bb28a93ff46327cfa1bd758a995529a868 100644
--- a/chrome/browser/media/android/router/media_router_android.cc
+++ b/chrome/browser/media/android/router/media_router_android.cc
@@ -104,6 +104,15 @@ void MediaRouterAndroid::CreateRoute(
       route_request_id);
 }
 
+void MediaRouterAndroid::JoinRouteByRouteId(
+    const MediaSource::Id& source,
+    const MediaRoute::Id& route_id,
+    const GURL& origin,
+    content::WebContents* web_contents,
+    const std::vector<MediaRouteResponseCallback>& callbacks) {
+  NOTIMPLEMENTED();
+}
+
 void MediaRouterAndroid::JoinRoute(
     const MediaSource::Id& source_id,
     const std::string& presentation_id,
@@ -259,14 +268,26 @@ void MediaRouterAndroid::UnregisterMediaSinksObserver(
 void MediaRouterAndroid::RegisterMediaRoutesObserver(
     MediaRoutesObserver* observer) {
   DVLOG(2) << "Added MediaRoutesObserver: " << observer;
-  routes_observers_.AddObserver(observer);
+  const std::string& source_id = observer->source_id();
+  base::ObserverList<MediaRoutesObserver>* observer_list =

[imcheng, 2015/11/26 00:49:45]

Use auto* so it's consistent with below.

[matt.boetger, 2015/12/01 01:26:55]

Reverting.

+      routes_observers_.get(source_id);
+  if (!observer_list) {

[imcheng, 2015/11/26 00:49:45]

It looks like we don't currently support joinable routes in the android
implementation because the implementation to notify observers of joinable routes
below is incorrect. There's also no need to support joinable routes on android.

I would suggest reverting the change here and then add something like:

if (!source_id.empty())
  NOTIMPLEMENTED() << "Joinable routes query not implemented."

[whywhat, 2015/11/26 14:43:04]

So actually, on Android it doesn't seem like we can identify running sessions
although we can try to join each device with a particular application id and if
it succeeds it means the route was joinable :)

By default, however, the Android SDK tries to join the application if it's
running, so we could at least tell the MR if the new route was a fresh session
or if it joined an already running application. Not sure if it's something MR
needs though.

[matt.boetger, 2015/12/01 01:26:55]

Done.

[matt.boetger, 2015/12/01 01:26:55]

Done.

+    observer_list = new base::ObserverList<MediaRoutesObserver>;
+    routes_observers_.add(source_id, make_scoped_ptr(observer_list));
+  } else {
+    DCHECK(!observer_list->HasObserver(observer));
+  }
+  observer_list->AddObserver(observer);
 }
 
 void MediaRouterAndroid::UnregisterMediaRoutesObserver(
     MediaRoutesObserver* observer) {
-  if (!routes_observers_.HasObserver(observer))
+  const std::string& source_id = observer->source_id();
+  auto* observer_list = routes_observers_.get(source_id);
+  if (!observer_list || !observer_list->HasObserver(observer))
     return;
-  routes_observers_.RemoveObserver(observer);
+
+  observer_list->RemoveObserver(observer);
 }
 
 void MediaRouterAndroid::RegisterIssuesObserver(IssuesObserver* observer) {
@@ -363,8 +384,13 @@ void MediaRouterAndroid::OnRouteCreated(
   route_requests_.Remove(jroute_request_id);
 
   active_routes_.push_back(route);
-  FOR_EACH_OBSERVER(MediaRoutesObserver, routes_observers_,
-                    OnRoutesUpdated(active_routes_));
+  for (auto it = routes_observers_.begin();
+       it != routes_observers_.end();
+       ++it) {
+    FOR_EACH_OBSERVER(MediaRoutesObserver, *it->second,
+        OnRoutesUpdated(active_routes_,
+            std::vector<MediaRoute::Id>()));
+  }
 }
 
 void MediaRouterAndroid::OnRouteRequestError(
@@ -394,8 +420,13 @@ void MediaRouterAndroid::OnRouteClosed(JNIEnv* env,
       break;
     }
 
-  FOR_EACH_OBSERVER(MediaRoutesObserver, routes_observers_,
-                    OnRoutesUpdated(active_routes_));
+  for (auto it = routes_observers_.begin();
+       it != routes_observers_.end();
+       ++it) {
+    FOR_EACH_OBSERVER(MediaRoutesObserver, *it->second,
+        OnRoutesUpdated(active_routes_,
+            std::vector<MediaRoute::Id>()));
+  }
 }
 
 void MediaRouterAndroid::OnMessageSentResult(