disable field trials if the build is 30 days or older

chrome/renderer/render_thread.cc

 // Copyright (c) 2010 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/renderer/render_thread.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 292 matching lines @@
 #endif
 
   // Establish a channel to the GPU process asynchronously if requested. If the
   // channel is established in time, EstablishGpuChannelSync will not block when
   // it is later called. Delays by a fixed period of time to avoid loading the
   // GPU immediately in an attempt to not slow startup time.
   scoped_refptr<base::FieldTrial> prelaunch_trial(
       new base::FieldTrial("PrelaunchGpuProcessExperiment", 100));
   int prelaunch_group = prelaunch_trial->AppendGroup("prelaunch_gpu_process",
                                                      kPrelauchGpuPercentage);
+  prelaunch_trial->AppendGroup("default_prelaunch_gpu_process",
+                               base::FieldTrial::kAllRemainingProbability);
   if (prelaunch_group == prelaunch_trial->group() ||
       CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kPrelaunchGpuProcess)) {
     message_loop()->PostDelayedTask(FROM_HERE,
                                     task_factory_->NewRunnableMethod(
                                         &RenderThread::EstablishGpuChannel),
                                     kPrelauchGpuProcessDelayMS);
   }
 
   TRACE_EVENT_END("RenderThread::Init", 0, "");
@@ skipping 827 matching lines @@
   }
 
   return false;
 }
 
 void RenderThread::RegisterExtension(v8::Extension* extension,
                                      bool restrict_to_extensions) {
   WebScriptController::registerExtension(extension);
   v8_extensions_[extension->name()] = restrict_to_extensions;
 }