Add Easy Unlock options to chrome://settings behind a flag.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 5ddd2f4af1267c13aebafbbe3cb5140688880c2a..9c07539a95a77a8f29cd96a34fbb52dc64d03566 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -574,6 +574,9 @@ const char kEnableDomDistiller[]               = "enable-dom-distiller";
 // Enable Enhanced Bookmarks.
 const char kEnhancedBookmarksExperiment[] = "enhanced-bookmarks-experiment";
 
+// Enables Easy Unlock to be set up and used.
+extern const char kEnableEasyUnlock[] = "enable-easy-unlock";
+
 // Enables experimentation with ephemeral apps, which are launched without
 // installing in Chrome.
 const char kEnableEphemeralApps[]           = "enable-ephemeral-apps";