Prepare MediaDrmBridge to work with MediaCodecPlayer

media/cdm/player_tracker_impl.cc

Index: media/cdm/player_tracker_impl.cc
diff --git a/media/cdm/player_tracker_impl.cc b/media/cdm/player_tracker_impl.cc
index 8f102bd724e18ac00a200e2bfb4efd330b040131..ff0e5f71e217339d433c4cb90a2082125782f78f 100644
--- a/media/cdm/player_tracker_impl.cc
+++ b/media/cdm/player_tracker_impl.cc
@@ -25,7 +25,10 @@ PlayerTrackerImpl::~PlayerTrackerImpl() {}
 
 int PlayerTrackerImpl::RegisterPlayer(const base::Closure& new_key_cb,
                                       const base::Closure& cdm_unset_cb) {
-  DCHECK(thread_checker_.CalledOnValidThread());
+  DVLOG(1) << "PlayerTrackerImpl::RegisterPlayer";
+
+  base::AutoLock lock(lock_);

[qinmin, 2015/09/15 21:10:45]

what is this lock trying to guard against? all these 4 methods here are called
by MediaDrmBridge, they should be on the same thread? no?

[Tima Vaisburd, 2015/09/15 23:48:56]

Yes, the MediaDrmBridge calls them on the same media thread. I added the lock
because I thought I need to implement the MediaDrmProxy methods RegisterPlayer()
and UnregisterPlayer(), they are part of the interface that we return. But it
seems they are never called ?

[Tima Vaisburd, 2015/09/16 01:26:29]

Removed the lock.

+
   int registration_id = next_registration_id_++;
   DCHECK(!ContainsKey(player_callbacks_map_, registration_id));
   player_callbacks_map_.insert(std::make_pair(
@@ -34,21 +37,32 @@ int PlayerTrackerImpl::RegisterPlayer(const base::Closure& new_key_cb,
 }
 
 void PlayerTrackerImpl::UnregisterPlayer(int registration_id) {
-  DCHECK(thread_checker_.CalledOnValidThread());
+  base::AutoLock lock(lock_);
+
   DCHECK(ContainsKey(player_callbacks_map_, registration_id))
       << registration_id;
   player_callbacks_map_.erase(registration_id);
 }
 
 void PlayerTrackerImpl::NotifyNewKey() {
+  // Ensure that callbacks are called on the same thread that created this
+  // class.
   DCHECK(thread_checker_.CalledOnValidThread());
+
+  base::AutoLock lock(lock_);
+
   std::map<int, PlayerCallbacks>::iterator iter = player_callbacks_map_.begin();
   for (; iter != player_callbacks_map_.end(); ++iter)
     iter->second.new_key_cb.Run();
 }
 
 void PlayerTrackerImpl::NotifyCdmUnset() {
+  // Ensure that callbacks are called on the same thread that created this
+  // class.
   DCHECK(thread_checker_.CalledOnValidThread());
+
+  base::AutoLock lock(lock_);
+
   std::map<int, PlayerCallbacks>::iterator iter = player_callbacks_map_.begin();
   for (; iter != player_callbacks_map_.end(); ++iter)
     iter->second.cdm_unset_cb.Run();