Revert of Hook up ProximityAuthSystem in EasyUnlockService.

chrome/browser/signin/chrome_proximity_auth_client.cc

Index: chrome/browser/signin/chrome_proximity_auth_client.cc
diff --git a/chrome/browser/signin/chrome_proximity_auth_client.cc b/chrome/browser/signin/chrome_proximity_auth_client.cc
index a5413fe816a5183d6304d5451f4ded75a88c608c..f8e13d69073ab3dd91b9e72fcaf3373d54c604db 100644
--- a/chrome/browser/signin/chrome_proximity_auth_client.cc
+++ b/chrome/browser/signin/chrome_proximity_auth_client.cc
@@ -105,10 +105,6 @@
 }
 
 std::string ChromeProximityAuthClient::GetAccountId() {
-  // There is no SigninManager for the login profile.
-  if (!SigninManagerFactory::GetForProfile(profile_))
-    return std::string();
-
   return SigninManagerFactory::GetForProfile(profile_)
       ->GetAuthenticatedAccountId();
 }