libmediaplayerservice: get isStreaming info from source.

Bug: 19061436
Change-Id: I0fc0d6207b0d3297d64aadab3e81448e3f3fa1de
diff --git a/media/libmediaplayerservice/nuplayer/GenericSource.h b/media/libmediaplayerservice/nuplayer/GenericSource.h
index 0a75e4c..dc85d2d 100644
--- a/media/libmediaplayerservice/nuplayer/GenericSource.h
+++ b/media/libmediaplayerservice/nuplayer/GenericSource.h
@@ -75,6 +75,8 @@
 
     virtual status_t setBuffers(bool audio, Vector<MediaBuffer *> &buffers);
 
+    virtual bool isStreaming() const;
+
 protected:
     virtual ~GenericSource();