[Sync] Move ModelType and related classes to 'syncer' namespace

sync/engine/conflict_resolver.cc

Index: sync/engine/conflict_resolver.cc
diff --git a/sync/engine/conflict_resolver.cc b/sync/engine/conflict_resolver.cc
index c10b21c9286006010ace05c9377b75622b3a9fdd..458c7ceb8bf42f459f6ff405511b496ec1abf175 100644
--- a/sync/engine/conflict_resolver.cc
+++ b/sync/engine/conflict_resolver.cc
@@ -31,9 +31,7 @@ using sessions::StatusController;
 using syncable::BaseTransaction;
 using syncable::Directory;
 using syncable::Entry;
-using syncable::GetModelTypeFromSpecifics;
 using syncable::Id;
-using syncable::IsRealDataType;
 using syncable::MutableEntry;
 using syncable::WriteTransaction;
 
@@ -223,7 +221,7 @@ ConflictResolver::ProcessSimpleConflict(WriteTransaction* trans,
     }
 
     // We manually merge nigori data.
-    if (entry.GetModelType() == syncable::NIGORI) {
+    if (entry.GetModelType() == syncer::NIGORI) {
       // Create a new set of specifics based on the server specifics (which
       // preserves their encryption keys).
       sync_pb::EntitySpecifics specifics =