Adding synthetic field trial for DataReductionProxyEnabled

chrome/browser/metrics/chrome_metrics_service_accessor.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/metrics/chrome_metrics_service_accessor.h"
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/common/pref_names.h"
 #include "components/metrics/metrics_service.h"
@@ skipping 28 matching lines @@
   // Android has its own settings for metrics / crash uploading.
   const PrefService* prefs = g_browser_process->local_state();
   return prefs->GetBoolean(prefs::kCrashReportingEnabled);
 #else
   return ChromeMetricsServiceAccessor::IsMetricsReportingEnabled();
 #endif
 #else
   return false;
 #endif
 }
+
+// static
+bool ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
+    const std::string& trial, const std::string& group) {
+  return MetricsServiceAccessor::RegisterSyntheticFieldTrial(
+      g_browser_process->metrics_service(),
+      trial,
+      group);
+}