Added an additional virtual method IStreamSource::flags().

Change-Id: I89e62d84328e12f08c8f73cbfd53cfb42569de97
diff --git a/include/media/IStreamSource.h b/include/media/IStreamSource.h
index 19646b0..61b9d5a 100644
--- a/include/media/IStreamSource.h
+++ b/include/media/IStreamSource.h
@@ -33,6 +33,12 @@
     virtual void setBuffers(const Vector<sp<IMemory> > &buffers) = 0;
 
     virtual void onBufferAvailable(size_t index) = 0;
+
+    enum {
+        // Video PES packets contain exactly one (aligned) access unit.
+        kFlagAlignedVideoData = 1,
+    };
+    virtual uint32_t flags() const { return 0; }
 };
 
 struct IStreamListener : public IInterface {