sync: add InternalComponentsFactory::Switches to simplify passing switches to internal components.

sync/sessions/sync_session.cc

Index: sync/sessions/sync_session.cc
diff --git a/sync/sessions/sync_session.cc b/sync/sessions/sync_session.cc
index f4329785378060a7750b70ff5e38d6e74790236c..ee296682111b4449f3c6f9e2b59b20ea579f5354 100644
--- a/sync/sessions/sync_session.cc
+++ b/sync/sessions/sync_session.cc
@@ -239,18 +239,13 @@ std::set<ModelSafeGroup>
 }
 
 namespace {
-// Return true if the command in question was attempted and did not complete
-// successfully.
-bool IsError(SyncerError error) {
-  return error != UNSET && error != SYNCER_OK;
-}
 
 // Returns false iff one of the command results had an error.
 bool HadErrors(const ModelNeutralState& state) {
-  const bool get_key_error = IsError(state.last_get_key_result);
+  const bool get_key_error = SyncerErrorIsError(state.last_get_key_result);
   const bool download_updates_error =
-      IsError(state.last_download_updates_result);
-  const bool commit_error = IsError(state.commit_result);
+      SyncerErrorIsError(state.last_download_updates_result);
+  const bool commit_error = SyncerErrorIsError(state.commit_result);
   return get_key_error || download_updates_error || commit_error;
 }
 }  // namespace