MediaCodec: add reset() + documentation fixes

Bug: 12034929
Change-Id: I38f89a2e4c41e0ceb3fdae4522b9c04f6c43a4f1
diff --git a/media/jni/android_media_MediaCodec.h b/media/jni/android_media_MediaCodec.h
index 2e650e3..dbccb0f 100644
--- a/media/jni/android_media_MediaCodec.h
+++ b/media/jni/android_media_MediaCodec.h
@@ -56,6 +56,7 @@
 
     status_t start();
     status_t stop();
+    status_t reset();
 
     status_t flush();