Adding synthetic field trial for DataReductionProxyEnabled

chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc

 // Copyright 2014 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/net/spdyproxy/data_reduction_proxy_chrome_settings.h"
 
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_configurator.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_configurator.h"
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_params.h"
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_settings.h"
+#include "components/metrics/metrics_service.h"
+#include "components/variations/metrics_util.h"
 
 using data_reduction_proxy::DataReductionProxyParams;
 using data_reduction_proxy::DataReductionProxySettings;
 
 DataReductionProxyChromeSettings::DataReductionProxyChromeSettings(
     DataReductionProxyParams* params) : DataReductionProxySettings(params) {
 }
 
 DataReductionProxyChromeSettings::~DataReductionProxyChromeSettings() {
 }
 
 void DataReductionProxyChromeSettings::InitDataReductionProxySettings(
     Profile* profile) {
   DCHECK(profile);
   PrefService* prefs = profile->GetPrefs();
 
   scoped_ptr<data_reduction_proxy::DataReductionProxyConfigurator>
       configurator(new DataReductionProxyChromeConfigurator(prefs));
   SetProxyConfigurator(configurator.Pass());
   DataReductionProxySettings::InitDataReductionProxySettings(
       prefs,
       g_browser_process->local_state(),
-      ProfileManager::GetActiveUserProfile()->GetRequestContext());
+      ProfileManager::GetActiveUserProfile()->GetRequestContext(),
+      base::Bind(&DataReductionProxyChromeSettings::RegisterSyntheticFieldTrial,
+                 base::Unretained(this)));
 
   SetDataReductionProxyAlternativeEnabled(
       DataReductionProxyParams::IsIncludedInAlternativeFieldTrial());
 }
+
+void DataReductionProxyChromeSettings::RegisterSyntheticFieldTrial(
+    bool data_reduction_proxy_enabled) {
+  if (g_browser_process->metrics_service()) {
+    SyntheticTrialGroup trial(
+        metrics::HashName("DataReductionProxyEnabled"),
+        metrics::HashName(data_reduction_proxy_enabled ? "true" : "false"));
+    g_browser_process->metrics_service()->RegisterSyntheticFieldTrial(trial);
+  }
+}