Allow proxying plaintext websockets over http/2 proxy

net/http/http_stream_factory_impl_job.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/http/http_stream_factory_impl_job.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 1146 matching lines @@
     RecordChannelIDKeyMatch(ssl_socket, session_->params().channel_id_service,
                             destination_.HostForURL());
   }
 
   // We only set the socket motivation if we're the first to use
   // this socket.  Is there a race for two SPDY requests?  We really
   // need to plumb this through to the connect level.
   if (connection_->socket() && !connection_->is_reused())
     SetSocketMotivation();
 
-  if (!using_spdy_) {
+  if (!using_spdy_)
     DCHECK(!IsSpdyAlternative());
+
+  // While websockets over HTTP/2 are not supported, it is still valid to have
+  // websockets tunneled through HTTP/2 proxy (via CONNECT). If websockets are
+  // secure (wss://), ProxyClientSocket with established tunnel is wrapped with
+  // yet another socket (SSLClientSocket), and |using_spdy_| will be false, but
+  // for ws: scheme, ProxyClientSocket is not wrapped into anything.
+  if (!using_spdy_ ||
+      (using_spdy_ && proxy_info_.is_https() && delegate_->for_websockets())) {
     // We may get ftp scheme when fetching ftp resources through proxy.
     bool using_proxy = (proxy_info_.is_http() || proxy_info_.is_https()) &&
                        (request_info_.url.SchemeIs(url::kHttpScheme) ||
                         request_info_.url.SchemeIs(url::kFtpScheme));
     if (delegate_->for_websockets()) {
       DCHECK_NE(job_type_, PRECONNECT);
       DCHECK(delegate_->websocket_handshake_stream_create_helper());
       websocket_stream_.reset(
           delegate_->websocket_handshake_stream_create_helper()
               ->CreateBasicStream(std::move(connection_), using_proxy));
@@ skipping 326 matching lines @@
 
   ConnectionAttempts socket_attempts = connection_->connection_attempts();
   if (connection_->socket()) {
     connection_->socket()->GetConnectionAttempts(&socket_attempts);
   }
 
   delegate_->AddConnectionAttemptsToRequest(this, socket_attempts);
 }
 
 }  // namespace net