Control easy unlock by a field trial.

chrome/browser/signin/easy_unlock.cc

Index: chrome/browser/signin/easy_unlock.cc
diff --git a/chrome/browser/signin/easy_unlock.cc b/chrome/browser/signin/easy_unlock.cc
index 62992119e3232bcdd42c105a7998b0cb8b4d2024..12ab6597e83c99850b64ea9768752d697f92b313 100644
--- a/chrome/browser/signin/easy_unlock.cc
+++ b/chrome/browser/signin/easy_unlock.cc
@@ -4,10 +4,13 @@
 
 #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"
@@ -40,4 +43,15 @@ void LaunchEasyUnlockSetup(Profile* profile) {
       profile, extension, extensions::LAUNCH_CONTAINER_WINDOW, NEW_WINDOW));
 }
 
+bool IsEnabled() {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableEasyUnlock)) {

[Alexei Svitkine (slow), 2014/07/22 18:18:41]

Please follow the pattern at the bottom of go/finch-and-flags.

[xiyuan, 2014/07/22 20:00:23]

Done.

+    return true;
+  }
+
+  const char kFieldTrialName[] = "EasyUnlock";
+  const char kEnable[] = "Enable";
+  return base::FieldTrialList::FindFullName(kFieldTrialName) == kEnable;
+}
+
 }  // namespace easy_unlock