Enable HTTP/2 by default.

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/base64.h"
 #include "base/bind.h"
@@ skipping 857 matching lines @@
     globals->use_alternate_protocols.set(true);
   } else if (spdy_trial_group.starts_with(
                  kSpdyFieldTrialSpdy4GroupNamePrefix)) {
     globals->next_protos = net::NextProtosSpdy4Http2();
     globals->use_alternate_protocols.set(true);
   } else if (spdy_trial_group == kSpdyFieldTrialSpdy4ControlGroupName) {
     // This control group is pinned at SPDY/3.1.
     globals->next_protos = net::NextProtosSpdy31();
     globals->use_alternate_protocols.set(true);
   } else {
-    // Use the current SPDY default (SPDY/3.1).
-    globals->next_protos = net::NextProtosSpdy31();
+    // By default, enable HTTP/2.
+    globals->next_protos = net::NextProtosSpdy4Http2();
     globals->use_alternate_protocols.set(true);
   }
 }
 
 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 517 matching lines @@
   net::QuicVersionVector supported_versions = net::QuicSupportedVersions();
   for (size_t i = 0; i < supported_versions.size(); ++i) {
     net::QuicVersion version = supported_versions[i];
     if (net::QuicVersionToString(version) == quic_version) {
       return version;
     }
   }
 
   return net::QUIC_VERSION_UNSUPPORTED;
 }