Could the logging code just be moved into QuicChromiumClientStream?  Seems like it's best to share code with HTTP-like HTTP2, if we can.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5fafe14b17f8ed28dc4e28adf17cbc699753413c

commit 5fafe14b17f8ed28dc4e28adf17cbc699753413c
Author: xunjieli <xunjieli@chromium.org>
Date: Wed Mar 23 23:32:54 2016

Add logging for headers sent and received in BidirectionalStreamQuicImpl

This CL refactors headers logging in QuicHttpStream and moves
them to QuicChromiumClientStream so the logging can be
shared with BidirectionalStreamQuicImpl.

BUG= 596680 

Review URL: https://codereview.chromium.org/1824403002

Cr-Commit-Position: refs/heads/master@{#382972}

[modify] https://crrev.com/5fafe14b17f8ed28dc4e28adf17cbc699753413c/net/log/net_log_event_type_list.h
[modify] https://crrev.com/5fafe14b17f8ed28dc4e28adf17cbc699753413c/net/quic/bidirectional_stream_quic_impl_unittest.cc
[modify] https://crrev.com/5fafe14b17f8ed28dc4e28adf17cbc699753413c/net/quic/quic_chromium_client_stream.cc
[modify] https://crrev.com/5fafe14b17f8ed28dc4e28adf17cbc699753413c/net/quic/quic_chromium_client_stream.h
[modify] https://crrev.com/5fafe14b17f8ed28dc4e28adf17cbc699753413c/net/quic/quic_http_stream.cc
[modify] https://crrev.com/5fafe14b17f8ed28dc4e28adf17cbc699753413c/net/quic/quic_http_stream_test.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bf0e46a7433eea99e1f0dc4f11cd1e950a786570

commit bf0e46a7433eea99e1f0dc4f11cd1e950a786570
Author: xunjieli <xunjieli@chromium.org>
Date: Tue Mar 29 21:50:23 2016

[Cronet] Initialize disable_quic_bidirectional_streams and QUIC protocol

BUG= 596680 

Review URL: https://codereview.chromium.org/1836983002

Cr-Commit-Position: refs/heads/master@{#383838}

[modify] https://crrev.com/bf0e46a7433eea99e1f0dc4f11cd1e950a786570/components/cronet/android/cronet_bidirectional_stream_adapter.cc
[add] https://crrev.com/bf0e46a7433eea99e1f0dc4f11cd1e950a786570/components/cronet/android/test/javatests/src/org/chromium/net/BidirectionalStreamQuicTest.java
[modify] https://crrev.com/bf0e46a7433eea99e1f0dc4f11cd1e950a786570/net/url_request/url_request_context_builder.cc