Implement WebSocketSpdyStreamAdapter.

WebSocketSpdyStreamAdapter wraps a SpdyStream so that it can be used by
the future WebSocketHttp2HandshakeStream class to do the  WebSocket
handshake, then handed off to WebSocketBasicStream.

Bug: 801564
Change-Id: Icac1d4e19d12b390bd61562de9150698be81f5f7
Reviewed-on: https://chromium-review.googlesource.com/912009
Reviewed-by: Ryan Hamilton <rch@chromium.org>
Reviewed-by: Adam Rice <ricea@chromium.org>
Commit-Queue: Bence Béky <bnc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537135}
5 files changed