Replace MidiFile player with a Midi extractor

This gets rids of a bunch of special midi handling and replaces it
with an extractor that works with NuPlayer and MediaMetadataRetriever.

Change-Id: I8d0f5bbdde2ca24267cf4d62ab26afe9630e0217
diff --git a/include/media/MidiIoWrapper.h b/include/media/MidiIoWrapper.h
index caf1d75..e6f8cf7 100644
--- a/include/media/MidiIoWrapper.h
+++ b/include/media/MidiIoWrapper.h
@@ -19,12 +19,15 @@
 
 #include <libsonivox/eas_types.h>
 
+#include "media/stagefright/DataSource.h"
+
 namespace android {
 
 class MidiIoWrapper : public RefBase {
 public:
     MidiIoWrapper(const char *path);
     MidiIoWrapper(int fd, off64_t offset, int64_t size);
+    MidiIoWrapper(const sp<DataSource> &source);
 
     ~MidiIoWrapper();
 
@@ -37,6 +40,7 @@
     int mFd;
     off64_t mBase;
     int64_t  mLength;
+    sp<DataSource> mDataSource;
     EAS_FILE mEasFile;
 };