[Sync] Log age of auth tokens on authentication failure

sync/engine/net/server_connection_manager.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SYNC_ENGINE_NET_SERVER_CONNECTION_MANAGER_H_
 #define SYNC_ENGINE_NET_SERVER_CONNECTION_MANAGER_H_
 
 #include <iosfwd>
 #include <string>
 
@@ skipping 206 matching lines @@
   // ThreadChecker thread, as we want to kill any pending http traffic without
   // having to wait for the request to complete.
   void TerminateAllIO();
 
   void set_client_id(const std::string& client_id) {
     DCHECK(thread_checker_.CalledOnValidThread());
     DCHECK(client_id_.empty());
     client_id_.assign(client_id);
   }
 
-  // Returns true if the auth token is succesfully set and false otherwise.
-  bool set_auth_token(const std::string& auth_token) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    if (previously_invalidated_token != auth_token) {
-      auth_token_.assign(auth_token);
-      previously_invalidated_token = std::string();
-      return true;
-    }
-    return false;
-  }
+  // 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);
 
   // 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
   // requests with known-bad tokens. This will put the
   // ServerConnectionManager in an auth error state as if it received an
   // HTTP 401 from sync servers.
   void OnInvalidationCredentialsRejected();
 
   bool HasInvalidAuthToken() {
     return auth_token_.empty();
@@ skipping 45 matching lines @@
 
   // Indicates whether or not requests should be made using HTTPS.
   bool use_ssl_;
 
   // The paths we post to.
   std::string proto_sync_path_;
 
   // 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;
 
   ObserverList<ServerConnectionEventListener> listeners_;
 
   HttpResponse::ServerConnectionCode server_status_;
 
   base::ThreadChecker thread_checker_;
 
   // Protects all variables below to allow bailing out of active connections.
@@ skipping 31 matching lines @@
   void NotifyStatusChanged();
 
   DISALLOW_COPY_AND_ASSIGN(ServerConnectionManager);
 };
 
 std::ostream& operator<<(std::ostream& s, const struct HttpResponse& hr);
 
 }  // namespace syncer
 
 #endif  // SYNC_ENGINE_NET_SERVER_CONNECTION_MANAGER_H_