Move test-only method from QuicFramer to quic_test_utils.

net/quic/test_tools/quic_test_utils.h

Index: net/quic/test_tools/quic_test_utils.h
diff --git a/net/quic/test_tools/quic_test_utils.h b/net/quic/test_tools/quic_test_utils.h
index 8bf069b4f62e0e9c8474963cfd191f5821fe4005..5367c760452c72bd48730521d348f63be204cde7 100644
--- a/net/quic/test_tools/quic_test_utils.h
+++ b/net/quic/test_tools/quic_test_utils.h
@@ -93,6 +93,13 @@ QuicAckFrame MakeAckFrame(QuicPacketSequenceNumber largest_observed,
 QuicAckFrame MakeAckFrameWithNackRanges(size_t num_nack_ranges,
                                         QuicPacketSequenceNumber least_unacked);
 
+// Returns a SerializedPacket whose |packet| member is owned by the caller,
+// and is populated with the fields in |header| and |frames|, or is NULL if
+// the packet could not be created.
+SerializedPacket BuildUnsizedDataPacket(QuicFramer* framer,
+                                        const QuicPacketHeader& header,
+                                        const QuicFrames& frames);
+
 template<typename SaveType>
 class ValueRestore {
  public: