Control easy unlock by a field trial.

chrome/browser/signin/easy_unlock.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/signin/easy_unlock.h"
 
+#include "base/command_line.h"
+#include "base/metrics/field_trial.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/extensions/application_launch.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "extensions/browser/extension_system.h"
 
 namespace easy_unlock {
 
 void RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   registry->RegisterBooleanPref(
       prefs::kEasyUnlockEnabled,
@@ skipping 12 matching lines @@
 void LaunchEasyUnlockSetup(Profile* profile) {
   ExtensionService* service =
       extensions::ExtensionSystem::Get(profile)->extension_service();
   const extensions::Extension* extension =
       service->GetExtensionById(extension_misc::kEasyUnlockAppId, false);
 
   OpenApplication(AppLaunchParams(
       profile, extension, extensions::LAUNCH_CONTAINER_WINDOW, NEW_WINDOW));
 }
 
+bool IsEnabled() {
+  const std::string group_name =
+      base::FieldTrialList::FindFullName("EasyUnlock");

[Andrew T Wilson (Slow), 2014/07/24 09:50:25]

Move this line down after the check for the command line switch.

[Alexei Svitkine (slow), 2014/07/24 14:10:26]

That will not produce correct results per go/finch-and-flags. Please instead add
a comment that this has to be before the command-line check to activate the
trial.

[xiyuan, 2014/07/25 17:47:26]

Done.

+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableEasyUnlock)) {
+    return true;
+  }
+  return group_name == "Enable";
+}
+
 }  // namespace easy_unlock