diff --git a/media/mtp/MtpDataPacket.h b/media/mtp/MtpDataPacket.h
index 759c0f9..9a24d61 100644
--- a/media/mtp/MtpDataPacket.h
+++ b/media/mtp/MtpDataPacket.h
@@ -22,6 +22,8 @@
 
 namespace android {
 
+class MtpStringBuffer;
+
 class MtpDataPacket : public MtpPacket {
 private:
     // current offset for get/put methods