Correct MediaMetadataCompat#METADATA_KEY_DATE Javadoc

Bug: 25080808
Change-Id: Iad2e2b317e05d9f50f91915a96297100bb935b82
diff --git a/v4/java/android/support/v4/media/MediaMetadataCompat.java b/v4/java/android/support/v4/media/MediaMetadataCompat.java
index 088b208..d6ebfa4 100644
--- a/v4/java/android/support/v4/media/MediaMetadataCompat.java
+++ b/v4/java/android/support/v4/media/MediaMetadataCompat.java
@@ -78,7 +78,8 @@
     public static final String METADATA_KEY_COMPILATION = "android.media.metadata.COMPILATION";
 
     /**
-     * The date the media was created or published as TODO determine format.
+     * The date the media was created or published. The format is unspecified
+     * but RFC 3339 is recommended.
      */
     public static final String METADATA_KEY_DATE = "android.media.metadata.DATE";