Use OAuth2 token for sync

sync/engine/net/server_connection_manager.h

Index: sync/engine/net/server_connection_manager.h
diff --git a/sync/engine/net/server_connection_manager.h b/sync/engine/net/server_connection_manager.h
index df81e265605dcecfb8f46008cc084003c108c13f..0b34ed455a39590f2c6cc3cb2f2167fec68056bc 100644
--- a/sync/engine/net/server_connection_manager.h
+++ b/sync/engine/net/server_connection_manager.h
@@ -224,11 +224,8 @@ class SYNC_EXPORT_PRIVATE ServerConnectionManager {
     client_id_.assign(client_id);
   }
 
-  // Sets a new auth token and time. |auth_token_time| is an optional parameter
-  // that contains the date the auth token was fetched/refreshed, and is used
-  // for histogramms/logging only.
-  bool SetAuthToken(const std::string& auth_token,
-                    const base::Time& auth_token_time);
+  // Sets a new auth token and time.
+  bool SetAuthToken(const std::string& auth_token);
 
   // Our out-of-band invalidations channel can encounter auth errors,
   // and when it does so it tells us via this method to prevent making more
@@ -294,10 +291,6 @@ class SYNC_EXPORT_PRIVATE ServerConnectionManager {
   // The auth token to use in authenticated requests.
   std::string auth_token_;
 
-  // The time at which this auth token was last created/refreshed.
-  // Used for histogramming.
-  base::Time auth_token_time_;
-
   // The previous auth token that is invalid now.
   std::string previously_invalidated_token;