Small cleanups in InvalidatorRegistrar

Updating comments, removing some unused members and some typedefs that
are only used a single time.

Bug: none
Change-Id: Icc7f37f9f0d8d9d7f707a5db6955726d0668b41e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1889653Reviewed-by: Tatiana Gornak <melandory@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710733}

components/invalidation/impl/invalidator_registrar.cc

@@ -75,9 +75,9 @@ Topics InvalidatorRegistrar::GetRegisteredTopics(
 Topics InvalidatorRegistrar::GetAllRegisteredIds() const {
   DCHECK(thread_checker_.CalledOnValidThread());
   Topics registered_ids;
-  for (auto it = handler_to_topics_map_.begin();
-       it != handler_to_topics_map_.end(); ++it) {
-    registered_ids.insert(it->second.begin(), it->second.end());
+  for (const auto& handler_and_topics : handler_to_topics_map_) {
+    const Topics& topics = handler_and_topics.second;
+    registered_ids.insert(topics.begin(), topics.end());
   }
   return registered_ids;
 }

components/invalidation/impl/invalidator_registrar.h

@@ -30,30 +30,29 @@ class INVALIDATION_EXPORT InvalidatorRegistrar {
   ~InvalidatorRegistrar();
 
   // Starts sending notifications to |handler|.  |handler| must not be NULL,
-  // and it must already be registered.
+  // and it must not already be registered.
   void RegisterHandler(InvalidationHandler* handler);
 
   // Stops sending notifications to |handler|.  |handler| must not be NULL, and
-  // it must already be registered.  Note that this doesn't unregister the IDs
-  // associated with |handler|.
+  // it must already be registered.  Note that this doesn't unregister the
+  // topics associated with |handler| from the server.
   void UnregisterHandler(InvalidationHandler* handler);
 
   // Updates the set of topics associated with |handler|.  |handler| must
   // not be NULL, and must already be registered.  A topic must be registered
-  // for at most one handler. If topic is already registered function returns
-  // false.
+  // for at most one handler. If any of the |topics| is already registered
+  // to a different handler, returns false.
   virtual bool UpdateRegisteredTopics(InvalidationHandler* handler,
                                       const Topics& topics) WARN_UNUSED_RESULT;
 
   virtual Topics GetRegisteredTopics(InvalidationHandler* handler) const;
 
-  // Returns the set of all IDs that are registered to some handler (even
-  // handlers that have been unregistered).
+  // Returns the set of all topics that are registered to some handler.
   virtual Topics GetAllRegisteredIds() const;
 
   // Sorts incoming invalidations into a bucket for each handler and then
   // dispatches the batched invalidations to the corresponding handler.
-  // Invalidations for IDs with no corresponding handler are dropped, as are
+  // Invalidations for topics with no corresponding handler are dropped, as are
   // invalidations for handlers that are not added.
   void DispatchInvalidationsToHandlers(
       const TopicInvalidationMap& invalidation_map);
@@ -74,21 +73,18 @@ class INVALIDATION_EXPORT InvalidatorRegistrar {
 
   // Gets a new map for the name of invalidator handlers and their
   // objects id. This is used by the InvalidatorLogger to be able
-  // to display every registered handlers and its objectsIds.
+  // to display every registered handler and its topics.
   std::map<std::string, Topics> GetSanitizedHandlersIdsMap();
 
   bool IsHandlerRegistered(const InvalidationHandler* handler) const;
-  bool HasRegisteredHandlers() const;
 
   // Needed for death tests.
   void DetachFromThreadForTest();
 
  private:
-  typedef std::map<InvalidationHandler*, Topics> HandlerTopicsMap;
-
   base::ThreadChecker thread_checker_;
   base::ObserverList<InvalidationHandler, true>::Unchecked handlers_;
-  HandlerTopicsMap handler_to_topics_map_;
+  std::map<InvalidationHandler*, Topics> handler_to_topics_map_;
   InvalidatorState state_;
 
   DISALLOW_COPY_AND_ASSIGN(InvalidatorRegistrar);

components/invalidation/impl/invalidator_registrar_with_memory.h

@@ -53,9 +53,6 @@ class INVALIDATION_EXPORT InvalidatorRegistrarWithMemory
   bool UpdateRegisteredTopics(InvalidationHandler* handler,
                               const Topics& topics) override WARN_UNUSED_RESULT;
 
-  // void UnregisterHandler(InvalidationHandler* handler) override;
-  // void RegisterHandler(InvalidationHandler* handler) override;
-
   // Returns the set of all IDs that are registered to some handler (even
   // handlers that have been unregistered).
   Topics GetAllRegisteredIds() const override;
@@ -65,14 +62,10 @@ class INVALIDATION_EXPORT InvalidatorRegistrarWithMemory
       const;
 
  private:
-  using HandlerNameTopicsMap = std::map<std::string, Topics>;
-
   // Generate a Dictionary with all the debugging information.
   base::DictionaryValue CollectDebugData() const;
 
-  std::unordered_map<std::string, InvalidationHandler*>
-      handler_name_to_handler_;
-  HandlerNameTopicsMap handler_name_to_topics_map_;
+  std::map<std::string, Topics> handler_name_to_topics_map_;
   PrefService* local_state_;
   const std::string sender_id_;