[Presentation API, Android] Implement routes observers

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

Index: chrome/browser/media/android/router/media_router_android.h
diff --git a/chrome/browser/media/android/router/media_router_android.h b/chrome/browser/media/android/router/media_router_android.h
index 42b182d6dd549f2df91a766fad2735008f9943db..9bdeda22b23ee5f542fa43c36059423a9a26101f 100644
--- a/chrome/browser/media/android/router/media_router_android.h
+++ b/chrome/browser/media/android/router/media_router_android.h
@@ -52,24 +52,27 @@ class MediaRouterAndroid : public MediaRouter {
 
   // JNI functions.
   void OnSinksReceived(
-      JNIEnv* env, jobject obj, jstring source_urn, jint count);
+      JNIEnv* env, jobject obj, jstring jsource_urn, jint jcount);
   void OnRouteCreated(
       JNIEnv* env,
       jobject obj,
-      jstring media_route_id,
+      jstring jmedia_route_id,
       jint jcreate_route_request_id,
       jboolean jis_local);
   void OnRouteCreationError(
       JNIEnv* env,
       jobject obj,
-      jstring error_text,
+      jstring jerror_text,
       jint jcreate_route_request_id);
+  void OnRouteClosed(JNIEnv* env, jobject obj, jstring jmedia_route_id);
 
  private:
   friend class MediaRouterFactory;
 
   explicit MediaRouterAndroid(content::BrowserContext*);
 
+  void UpdateRoutesObservers();
+
   // MediaRouter implementation.
   void RegisterMediaSinksObserver(MediaSinksObserver* observer) override;
   void UnregisterMediaSinksObserver(MediaSinksObserver* observer) override;
@@ -89,6 +92,8 @@ class MediaRouterAndroid : public MediaRouter {
       scoped_ptr<base::ObserverList<MediaSinksObserver>>>;
   MediaSinkObservers sinks_observers_;
 
+  base::ObserverList<MediaRoutesObserver> routes_observers_;
+
   struct CreateMediaRouteRequest {
     CreateMediaRouteRequest(
         const MediaSource& source,
@@ -107,6 +112,10 @@ class MediaRouterAndroid : public MediaRouter {
       IDMap<CreateMediaRouteRequest, IDMapOwnPointer>;
   CreateMediaRouteRequests create_route_requests_;
 
+  using MediaRoutes = base::ScopedPtrHashMap<
+      MediaRoute::Id, scoped_ptr<MediaRoute>>;
+  MediaRoutes active_routes_;

[mlamouri (slow - plz ping), 2015/08/18 22:39:37]

FWIW, I'm not sure if it is really helping to have a HashMap. Every time you
modify the map (O(1)), you end up creating a vector from that map (O(n)). So,
basically, it boils down to a O(n) operation. I wonder if it wouldn't be better
to simply have a vector for active_routes_ so at least you save creating a new
vector on the stack when there are changes.

Obviously, I do not have the big picture so maybe this map might come handy with
future CLs.

[whywhat, 2015/08/19 00:26:43]

Agreed. I don't think a map is needed in the future - we need a map from route
id to session id which already exists on the Java side. (unless there's a hope
that MediaRoutesObserver and MediaRouter Mojo interfaces are improved and we
don't have to pass all the routes in a vector each time :) Perhaps it's easier
to pass this array from JS of the component extension.

+
   DISALLOW_COPY_AND_ASSIGN(MediaRouterAndroid);
 };