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 4efecb81d9df7a75fd2dfb63e9dd6e4f5d64066b..594d30aa3ec0eae5087a0c1babea8099548127d9 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -528,6 +528,9 @@ const char kEnableDomainReliability[]          = "enable-domain-reliability";
 // 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";