API Extension: Support for optionally specifying a map of extra request headers when specifying the uri of media data to be played.

related-to-bug: 2393577

Original change by Andrei Popescu <andreip@google.com>
diff --git a/media/libmediaplayerservice/MidiMetadataRetriever.cpp b/media/libmediaplayerservice/MidiMetadataRetriever.cpp
index 3795b7b..ad95fac 100644
--- a/media/libmediaplayerservice/MidiMetadataRetriever.cpp
+++ b/media/libmediaplayerservice/MidiMetadataRetriever.cpp
@@ -43,7 +43,8 @@
     if (mMidiPlayer == 0) {
         mMidiPlayer = new MidiFile();
     }
-    return mMidiPlayer->setDataSource(url);
+    // TODO: support headers in MetadataRetriever interface!
+    return mMidiPlayer->setDataSource(url, NULL /* headers */);
 }
 
 status_t MidiMetadataRetriever::setDataSource(int fd, int64_t offset, int64_t length)