tree d0df12aba9ac2e3ba6fd2ed00d9964688942c55f
parent 7d4f913c7d5a87fca15fc7d26dc343ee11ff7754
author bnc <bnc@google.com> 1561086590 -0700
committer Copybara-Service <copybara-worker@google.com> 1561147445 -0700

Make QpackEncoder interface not progressive.

When the QPACK implementation was originally written, an
HpackEncoder::ProgressiveEncoder interface was used for encoding.  However, the
way it is used in QuicSpdyStream, it is clear now that encoding can be done in a
single pass into a std::string object.  QuicStream::WriteOrBufferData() does not
lend itself easily to notifying the QPACK encoder that it is ready to take more
data.  Instead it is more natural to encode the entire header block and buffer
that in QuicStreamSendBuffer.  Also note that this should not cost more memory
than doing progressive encoding, because the SpdyHeaderBlock object would need
to be kept around if progressive encoding was used.

This CL introduces no functional change, it just changes the interface, and
moves the code that calls Next() from QuicSpdyStream into QpackEncoder.  A
follow-up CL will clean up QpackEncoder internals.

gfe-relnote: n/a, QUIC v99-only change.
PiperOrigin-RevId: 254323435
Change-Id: Ic3d203ed9f019ad01dba61d407a6e73bde5d12d1