Add message id to interface

In order to synchronize message id when a new connection is made,
message Id is added as a return value. Also the last posted message Id
is given as paramter, when observer is notfied of new messages.

Bug: 112203066
Change-Id: Ic3921fd176aec1abc7de3ea88c730ad46182d28f

media/bufferpool/2.0/IAccessor.hal

@@ -67,6 +67,7 @@ interface IAccessor {
      *     to get shared buffers from the buffer pool.
      * @return connectionId Id of IConnection. The Id identifies
      *     sender and receiver in FMQ messages during buffer transfer.
+     * @return msgId Id of the most recent message from buffer pool.
      * @return toFmqDesc FMQ descriptor. The descriptor is used to
      *     post buffer status messages.
      * @return fromFmqDesc FMQ descriptor. The descriptor is used to
@@ -75,6 +76,7 @@ interface IAccessor {
     connect(IObserver observer)
         generates (ResultStatus status, IConnection connection,
                    int64_t connectionId,
+                   uint32_t msgId,
                    fmq_sync<BufferStatusMessage> toFmqDesc,
                    fmq_unsync<BufferInvalidationMessage> fromFmqDesc);
 };

media/bufferpool/2.0/IObserver.hal

@@ -29,6 +29,7 @@ interface IObserver {
      * message.
      *
      * @param connectionId the connection Id of the specific buffer pool client
+     * @param msgId Id of the most recent message
      */
-    oneway onMessage(int64_t connectionId);
+    oneway onMessage(int64_t connectionId, uint32_t msgId);
 };