media: document VP9 CSD for MediaCodec

Also document that concatenated CSD is only supported for AVC.

Bug: 10672559
Change-Id: I54867655068802ef35f92a6341f8b5bb068555ee

media/java/android/media/MediaCodec.java

@@ -226,8 +226,8 @@ import java.util.Map;
  Codec-specific data in the format is automatically submitted to the codec upon {@link #start};
  you <strong>MUST NOT</strong> submit this data explicitly. If the format did not contain codec
  specific data, you can choose to submit it using the specified number of buffers in the correct
- order, according to the format requirements. Alternately, you can concatenate all codec-specific
- data and submit it as a single codec-config buffer.
+ order, according to the format requirements. In case of H.264 AVC, you can also concatenate all
+ codec-specific data and submit it as a single codec-config buffer.
  <p>
  Android uses the following codec-specific data buffers. These are also required to be set in
  the track format for proper {@link MediaMuxer} track configuration. Each parameter set and the
@@ -284,6 +284,13 @@ import java.util.Map;
     <td class=NA>Not Used</td>
     <td class=NA>Not Used</td>
    </tr>
+   <tr>
+    <td>VP9</td>
+    <td>VP9 <a href="http://wiki.webmproject.org/vp9-codecprivate">CodecPrivate</a> Data
+        (optional)</td>
+    <td class=NA>Not Used</td>
+    <td class=NA>Not Used</td>
+   </tr>
   </tbody>
  </table>