Add one-time randomization support for FieldTrial, and the ability to

net/socket/client_socket_pool_histograms.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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/socket/client_socket_pool_histograms.h"
 
 #include <string>
 
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "net/socket/client_socket_handle.h"
@@ skipping 39 matching lines @@
 ClientSocketPoolHistograms::~ClientSocketPoolHistograms() {
 }
 
 void ClientSocketPoolHistograms::AddSocketType(int type) const {
   socket_type_->Add(type);
 }
 
 void ClientSocketPoolHistograms::AddRequestTime(base::TimeDelta time) const {
   request_time_->AddTime(time);
 
-  static bool proxy_connection_impact_trial_exists(
-      base::FieldTrialList::Find("ProxyConnectionImpact") &&
-      !base::FieldTrialList::Find("ProxyConnectionImpact")->
-          group_name().empty());
+  static const bool proxy_connection_impact_trial_exists =
+      base::FieldTrialList::TrialExists("ProxyConnectionImpact");
   if (proxy_connection_impact_trial_exists && is_http_proxy_connection_) {
     UMA_HISTOGRAM_CUSTOM_TIMES(
         base::FieldTrial::MakeName("Net.HttpProxySocketRequestTime",
                              "ProxyConnectionImpact"),
         time,
         base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromMinutes(10),
         100);
   }
   if (proxy_connection_impact_trial_exists && is_socks_connection_) {
     UMA_HISTOGRAM_CUSTOM_TIMES(
         base::FieldTrial::MakeName("Net.SocksSocketRequestTime",
                              "ProxyConnectionImpact"),
         time,
         base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromMinutes(10),
         100);
   }
 }
 
 void ClientSocketPoolHistograms::AddUnusedIdleTime(base::TimeDelta time) const {
   unused_idle_time_->AddTime(time);
 }
 
 void ClientSocketPoolHistograms::AddReusedIdleTime(base::TimeDelta time) const {
   reused_idle_time_->AddTime(time);
 }
 
 }  // namespace net