Add a queued_data_bytes() method to ReliableQuicStream. Not used outside of tests.

net/quic/reliable_quic_stream.h

Index: net/quic/reliable_quic_stream.h
diff --git a/net/quic/reliable_quic_stream.h b/net/quic/reliable_quic_stream.h
index 096770c4fac0c8bf21d9eeb12f2a99fc3e1adcdd..3ea970b60da0fb783ebabd5bdca2563211966298 100644
--- a/net/quic/reliable_quic_stream.h
+++ b/net/quic/reliable_quic_stream.h
@@ -113,6 +113,8 @@ class NET_EXPORT_PRIVATE ReliableQuicStream {
   bool fin_received() { return fin_received_; }
   bool fin_sent() { return fin_sent_; }
 
+  uint64 queued_data_bytes() const { return queued_data_bytes_; }
+
   uint64 stream_bytes_read() const { return stream_bytes_read_; }
   uint64 stream_bytes_written() const { return stream_bytes_written_; }
 
@@ -246,6 +248,8 @@ class NET_EXPORT_PRIVATE ReliableQuicStream {
   void MaybeSendBlocked();
 
   std::list<PendingData> queued_data_;
+  // How many bytes are queued?
+  uint64 queued_data_bytes_;
 
   QuicStreamSequencer sequencer_;
   QuicStreamId id_;