Check for duplicate id strings in ChunkDemuxer::AddId()

WebKit's MediaSource object keeps a private member variable, int m_nextSourceBufferId, for adding source ids since ids are no longer part of the spec.  It is possible that this int could wrap around if several source buffers are added.  To ensure this doesn't cause problems, ChunkDemuxer::AddId() should check the id string to make sure it is not a duplicate and, if so, throw a ReachedIdLimit error.

BUG=140861


Review URL: https://chromiumcodereview.appspot.com/10830185

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150459 0039d316-1c4b-4281-b951-d872f2087c98

media/filters/chunk_demuxer.cc

@@ -611,7 +611,8 @@ ChunkDemuxer::Status ChunkDemuxer::AddId(const std::string& id,
   DCHECK_GT(codecs.size(), 0u);
   base::AutoLock auto_lock(lock_);
 
-  if (state_ != WAITING_FOR_INIT && state_ != INITIALIZING)
+  if ((state_ != WAITING_FOR_INIT && state_ != INITIALIZING) ||
+      stream_parser_map_.count(id) > 0u)
     return kReachedIdLimit;
 
   bool has_audio = false;