[Sync] Move sync/{internal_api,syncable} into syncer namespace

sync/engine/syncer.cc

Index: sync/engine/syncer.cc
diff --git a/sync/engine/syncer.cc b/sync/engine/syncer.cc
index 3e8e456a019e8011a05b8b1b75a0684127edbf8b..ff28c738626cf6aa8d50aa4105922290593aac67 100644
--- a/sync/engine/syncer.cc
+++ b/sync/engine/syncer.cc
@@ -31,6 +31,13 @@
 using base::Time;
 using base::TimeDelta;
 using sync_pb::ClientCommand;
+
+namespace syncer {
+
+using sessions::ScopedSessionContextConflictResolver;
+using sessions::StatusController;
+using sessions::SyncSession;
+using sessions::ConflictProgress;
 using syncable::IS_UNAPPLIED_UPDATE;
 using syncable::SERVER_CTIME;
 using syncable::SERVER_IS_DEL;
@@ -42,13 +49,6 @@ using syncable::SERVER_POSITION_IN_PARENT;
 using syncable::SERVER_SPECIFICS;
 using syncable::SERVER_VERSION;
 
-namespace syncer {
-
-using sessions::ScopedSessionContextConflictResolver;
-using sessions::StatusController;
-using sessions::SyncSession;
-using sessions::ConflictProgress;
-
 #define ENUM_CASE(x) case x: return #x
 const char* SyncerStepToString(const SyncerStep step)
 {