[SPDY] Add flag to turn on SPDY/3.1 (with per-session flow control)

chrome/browser/io_thread.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 "chrome/browser/io_thread.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 631 matching lines @@
     globals_->max_spdy_sessions_per_domain.set(
         GetSwitchValueAsInt(command_line, switches::kMaxSpdySessionsPerDomain));
   }
   if (command_line.HasSwitch(switches::kMaxSpdyConcurrentStreams)) {
     globals_->max_spdy_concurrent_streams_limit.set(
         GetSwitchValueAsInt(command_line, switches::kMaxSpdyConcurrentStreams));
   }
   if (command_line.HasSwitch(switches::kIgnoreUrlFetcherCertRequests))
     net::URLFetcher::SetIgnoreCertificateRequests(true);
 
-  bool used_spdy_switch = false;
   if (command_line.HasSwitch(switches::kUseSpdy)) {
     std::string spdy_mode =
         command_line.GetSwitchValueASCII(switches::kUseSpdy);
     EnableSpdy(spdy_mode);
-    used_spdy_switch = true;
-  }
-  if (command_line.HasSwitch(switches::kEnableSpdy3)) {
+  } else if (command_line.HasSwitch(switches::kEnableSpdy31)) {
+    net::HttpStreamFactory::EnableNpnSpdy31();
+  } else if (command_line.HasSwitch(switches::kEnableSpdy3)) {
     net::HttpStreamFactory::EnableNpnSpdy3();
-    used_spdy_switch = true;
   } else if (command_line.HasSwitch(switches::kEnableNpn)) {
     net::HttpStreamFactory::EnableNpnSpdy();
-    used_spdy_switch = true;
   } else if (command_line.HasSwitch(switches::kEnableNpnHttpOnly)) {
     net::HttpStreamFactory::EnableNpnHttpOnly();
-    used_spdy_switch = true;
-  }
-  if (!used_spdy_switch) {
+  } else {
+    // Use SPDY/3 by default.
     net::HttpStreamFactory::EnableNpnSpdy3();
   }
 }
 
 void IOThread::EnableSpdy(const std::string& mode) {
   static const char kOff[] = "off";
   static const char kSSL[] = "ssl";
   static const char kDisableSSL[] = "no-ssl";
   static const char kDisablePing[] = "no-ping";
   static const char kExclude[] = "exclude";  // Hosts to exclude
@@ skipping 222 matching lines @@
   globals_->system_request_context.reset(
       ConstructSystemRequestContext(globals_, net_log_));
 
   sdch_manager_->set_sdch_fetcher(
       new SdchDictionaryFetcher(system_url_request_context_getter_.get()));
 }
 
 void IOThread::UpdateDnsClientEnabled() {
   globals()->host_resolver->SetDnsClientEnabled(*dns_client_enabled_);
 }