Update EME MediaKeyNeededEvent.initData for ISO BMFF to match current spec.

media/mp4/mp4_stream_parser.h

Index: media/mp4/mp4_stream_parser.h
diff --git a/media/mp4/mp4_stream_parser.h b/media/mp4/mp4_stream_parser.h
index 4c8df36d9b8d65869620867474858d76801d7190..41b82720bf041d36bd8f08a1305b3d8aaa98b722 100644
--- a/media/mp4/mp4_stream_parser.h
+++ b/media/mp4/mp4_stream_parser.h
@@ -48,7 +48,9 @@ class MEDIA_EXPORT MP4StreamParser : public StreamParser {
   bool ParseMoov(mp4::BoxReader* reader);
   bool ParseMoof(mp4::BoxReader* reader);
 
-  bool EmitKeyNeeded(const TrackEncryption& track_encryption);
+  // Returns 'true' if sent or not required, 'false' if there was an error.
+  bool EmitNeedKeyIfNecessary(
+      const std::vector<ProtectionSystemSpecificHeader>& headers);
 
   // To retain proper framing, each 'mdat' atom must be read; to limit memory
   // usage, the atom's data needs to be discarded incrementally as frames are