[Sync] SyncEngine refactor part 1: interfaces.

components/sync/driver/sync_api_component_factory.h

Index: components/sync/driver/sync_api_component_factory.h
diff --git a/components/sync/driver/sync_api_component_factory.h b/components/sync/driver/sync_api_component_factory.h
index 7c1ac75abf5cad4513e21fb080516cfcae99bd0b..9c49882b8aa455056875291cd4adf32ca888c5f7 100644
--- a/components/sync/driver/sync_api_component_factory.h
+++ b/components/sync/driver/sync_api_component_factory.h
@@ -32,7 +32,7 @@ class DataTypeEncryptionHandler;
 class DataTypeManager;
 class DataTypeManagerObserver;
 class LocalDeviceInfoProvider;
-class SyncBackendHost;
+class SyncEngine;
 class SyncClient;
 class SyncPrefs;
 class SyncService;
@@ -78,18 +78,18 @@ class SyncApiComponentFactory {
       SyncService* sync_service,
       const RegisterDataTypesMethod& register_platform_types_method) = 0;
 
-  // Instantiates a new DataTypeManager with a SyncBackendHost, a list of data
+  // Instantiates a new DataTypeManager with a SyncEngine, a list of data

[skym, 2016/12/02 20:54:54]

This is kind of stating the obvious. Yes, we know it takes a SyncEngine and a
DataTypeManagerObserser, those are literally the arguments below. Doesn't
actually take a list of DTCs, but actually a map. Might be valuable to just
remove the first sentence here.

[maxbogue, 2016/12/02 23:59:27]

Done.

   // type controllers and a DataTypeManagerObserver.  The return pointer is
   // owned by the caller.
   virtual DataTypeManager* CreateDataTypeManager(
       const WeakHandle<DataTypeDebugInfoListener>& debug_info_listener,
       const DataTypeController::TypeMap* controllers,
       const DataTypeEncryptionHandler* encryption_handler,
-      SyncBackendHost* backend,
+      SyncEngine* engine,
       DataTypeManagerObserver* observer) = 0;
 
   // Creating this in the factory helps us mock it out in testing.
-  virtual SyncBackendHost* CreateSyncBackendHost(
+  virtual SyncEngine* CreateSyncEngine(
       const std::string& name,
       invalidation::InvalidationService* invalidator,
       const base::WeakPtr<SyncPrefs>& sync_prefs,