sync: Introduce ModelTypeRegistry and helpers

sync/sessions/sync_session_context.cc

Index: sync/sessions/sync_session_context.cc
diff --git a/sync/sessions/sync_session_context.cc b/sync/sessions/sync_session_context.cc
index f8bc275b304bd22326f6bf94b08804bb063859da..36e6343b0fa59904e2ba3303fda8fd740f4972dd 100644
--- a/sync/sessions/sync_session_context.cc
+++ b/sync/sessions/sync_session_context.cc
@@ -13,33 +13,27 @@ namespace sessions {
 SyncSessionContext::SyncSessionContext(
     ServerConnectionManager* connection_manager,
     syncable::Directory* directory,
-    const std::vector<scoped_refptr<ModelSafeWorker> >& workers,
     ExtensionsActivity* extensions_activity,
     const std::vector<SyncEngineEventListener*>& listeners,
     DebugInfoGetter* debug_info_getter,
     TrafficRecorder* traffic_recorder,
+    ModelTypeRegistry* model_type_registry,
     bool keystore_encryption_enabled,
     bool client_enabled_pre_commit_update_avoidance,
     const std::string& invalidator_client_id)
     : connection_manager_(connection_manager),
       directory_(directory),
-      update_handler_deleter_(&update_handler_map_),
-      commit_contributor_deleter_(&commit_contributor_map_),
       extensions_activity_(extensions_activity),
       notifications_enabled_(false),
       max_commit_batch_size_(kDefaultMaxCommitBatchSize),
       debug_info_getter_(debug_info_getter),
       traffic_recorder_(traffic_recorder),
+      model_type_registry_(model_type_registry),
       keystore_encryption_enabled_(keystore_encryption_enabled),
       invalidator_client_id_(invalidator_client_id),
       server_enabled_pre_commit_update_avoidance_(false),
       client_enabled_pre_commit_update_avoidance_(
           client_enabled_pre_commit_update_avoidance) {
-  for (size_t i = 0u; i < workers.size(); ++i) {
-    workers_.insert(
-        std::make_pair(workers[i]->GetModelSafeGroup(), workers[i]));
-  }
-
   std::vector<SyncEngineEventListener*>::const_iterator it;
   for (it = listeners.begin(); it != listeners.end(); ++it)
     listeners_.AddObserver(*it);
@@ -48,31 +42,10 @@ SyncSessionContext::SyncSessionContext(
 SyncSessionContext::~SyncSessionContext() {
 }
 
-void SyncSessionContext::set_routing_info(
+void SyncSessionContext::SetRoutingInfo(
     const ModelSafeRoutingInfo& routing_info) {
   enabled_types_ = GetRoutingInfoTypes(routing_info);
-
-  // TODO(rlarocque): This is not a good long-term solution.  We must find a
-  // better way to initialize the set of CommitContributors and UpdateHandlers.
-  STLDeleteValues<UpdateHandlerMap>(&update_handler_map_);
-  STLDeleteValues<CommitContributorMap>(&commit_contributor_map_);
-  for (ModelSafeRoutingInfo::const_iterator routing_iter = routing_info.begin();
-       routing_iter != routing_info.end(); ++routing_iter) {
-    ModelType type = routing_iter->first;
-    ModelSafeGroup group = routing_iter->second;
-    std::map<ModelSafeGroup, scoped_refptr<ModelSafeWorker> >::iterator
-        worker_it = workers_.find(group);
-    DCHECK(worker_it != workers_.end());
-    scoped_refptr<ModelSafeWorker> worker = worker_it->second;
-
-    SyncDirectoryUpdateHandler* handler =
-        new SyncDirectoryUpdateHandler(directory(), type, worker);
-    update_handler_map_.insert(std::make_pair(type, handler));
-
-    SyncDirectoryCommitContributor* contributor =
-        new SyncDirectoryCommitContributor(directory(), type);
-    commit_contributor_map_.insert(std::make_pair(type, contributor));
-  }
+  model_type_registry_->SetEnabledDirectoryTypes(routing_info);
 }
 
 }  // namespace sessions