Comments updated as result of infinite timeout for state keys generated

chrome/browser/chromeos/policy/server_backed_state_keys_broker.h

 // Copyright 2014 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 CHROME_BROWSER_CHROMEOS_POLICY_SERVER_BACKED_STATE_KEYS_BROKER_H_
 #define CHROME_BROWSER_CHROMEOS_POLICY_SERVER_BACKED_STATE_KEYS_BROKER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 28 matching lines @@
       chromeos::SessionManagerClient* session_manager_client,
       scoped_refptr<base::TaskRunner> delayed_task_runner);
   ~ServerBackedStateKeysBroker();
 
   // Registers a callback to be invoked whenever the state keys get updated.
   // Note that consuming code needs to hold on to the returned Subscription as
   // long as it wants to receive the callback. If the state keys haven't been
   // requested yet, calling this will also trigger their initial fetch.
   Subscription RegisterUpdateCallback(const base::Closure& callback);
 
-  // Requests state keys asynchronously. Invokes the passed callback exactly
-  // once (unless |this| gets destroyed before the callback happens), with the
-  // current state keys passed as a parameter to the callback. If there's a
-  // problem determining the state keys, the passed vector will be empty.
+  // Requests state keys asynchronously. Invokes the passed callback at most
+  // once, with the current state keys passed as a parameter to the callback. If
+  // there's a problem determining the state keys, the passed vector will be
+  // empty. If |this| gets destroyed before the callback happens or if the time
+  // sync fails / the network is not established, then the |callback| is never
+  // invoked. See http://crbug.com/649422 for more context.
   void RequestStateKeys(const StateKeysCallback& callback);
 
   // Get the set of current state keys. Empty if state keys are unavailable
   // or pending retrieval.
   const std::vector<std::string>& state_keys() const { return state_keys_; }
 
   // Returns the state key for the current point in time. Returns an empty
   // string if state keys are unavailable or pending retrieval.
   std::string current_state_key() const {
     return state_keys_.empty() ? std::string() : state_keys_.front();
@@ skipping 32 matching lines @@
   std::vector<StateKeysCallback> request_callbacks_;
 
   base::WeakPtrFactory<ServerBackedStateKeysBroker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServerBackedStateKeysBroker);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_CHROMEOS_POLICY_SERVER_BACKED_STATE_KEYS_BROKER_H_