Add Spdy4Experiment group.

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 116 matching lines @@
 //  * A "holdback" group with SPDY disabled, and corresponding control
 //  (SPDY/3.1). The primary purpose of the holdback group is to encourage site
 //  operators to do feature detection rather than UA-sniffing. As such, this
 //  trial runs continuously.
 //  * A SPDY/4 experiment, for SPDY/4 (aka HTTP/2) vs SPDY/3.1 comparisons and
 //  eventual SPDY/4 deployment.
 const char kSpdyFieldTrialName[] = "SPDY";
 const char kSpdyFieldTrialHoldbackGroupName[] = "SpdyDisabled";
 const char kSpdyFieldTrialHoldbackControlGroupName[] = "Control";
 const char kSpdyFieldTrialSpdy4GroupName[] = "Spdy4Enabled";
+const char kSpdyFieldTrialSpdy4ExperimentGroupName[] = "Spdy4Experiment";
 const char kSpdyFieldTrialSpdy4ControlGroupName[] = "Spdy4Control";
 
 // Field trial for Cache-Control: stale-while-revalidate directive.
 const char kStaleWhileRevalidateFieldTrialName[] = "StaleWhileRevalidate";
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 void ObserveKeychainEvents() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   net::CertDatabase::GetInstance()->SetMessageLoopForKeychainEvents();
 }
@@ skipping 687 matching lines @@
 
 void IOThread::ConfigureSpdyFromTrial(const std::string& spdy_trial_group,
                                       Globals* globals) {
   if (spdy_trial_group == kSpdyFieldTrialHoldbackGroupName) {
     // TODO(jgraettinger): Use net::NextProtosHttpOnly() instead?
     net::HttpStreamFactory::set_spdy_enabled(false);
   } else if (spdy_trial_group == kSpdyFieldTrialHoldbackControlGroupName) {
     // Use the current SPDY default (SPDY/3.1).
     globals->next_protos = net::NextProtosSpdy31();
     globals->use_alternate_protocols.set(true);
   } else if (spdy_trial_group == kSpdyFieldTrialSpdy4GroupName) {

[Ryan Hamilton, 2014/10/30 17:34:32]

We've been doing a lot of finch config work with QUIC lately. An alternative is
to do something like:

if (spdy_trail_group.starts_with(kSpdyFieldTrialSpdy4GroupName) {
  ..
}

Then you can create an unlimited number of different group names without needing
to change the code.  The other thing you could consider would be do something
like we do with QUIC where we make use of params in each field trial group to
control various knobs explicitly, instead of needing to look at/parse out the
group name.

I think it would be better to pursue one of these approaches rather than
hardcoding a new group name in the code.

What do you think?

[Bence, 2014/10/30 18:39:03]

This is a great idea.  I am extenting this to SpdyDisabled, and adding
Spdy31Enabled.  This will allow us to deprecate *Control*, and have a clearer
group layout, like:
* SpdyDisabled-5
* Spdy31Enabled-5
* Spdy4Enabled-5
* Spdy4Enabled-rest

     globals->next_protos = net::NextProtosSpdy4Http2();
     globals->use_alternate_protocols.set(true);
+  } else if (spdy_trial_group == kSpdyFieldTrialSpdy4ExperimentGroupName) {
+    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();
     globals->use_alternate_protocols.set(true);
   }
 }
@@ skipping 575 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;
 }