[Sync] Renaming client key to client tag.

sync/internal_api/model_type_entity.cc

Index: sync/internal_api/model_type_entity.cc
diff --git a/sync/internal_api/model_type_entity.cc b/sync/internal_api/model_type_entity.cc
index c4894256b15b9532485aa2067a0aa7b35d3677d2..a88fab09ab2801116d3c58e710859b210972a1e5 100644
--- a/sync/internal_api/model_type_entity.cc
+++ b/sync/internal_api/model_type_entity.cc
@@ -34,9 +34,9 @@ scoped_ptr<ModelTypeEntity> ModelTypeEntity::CreateNew(
       new ModelTypeEntity(client_tag, &metadata));
 }
 
-ModelTypeEntity::ModelTypeEntity(const std::string& client_key,
+ModelTypeEntity::ModelTypeEntity(const std::string& client_tag,
                                  sync_pb::EntityMetadata* metadata)
-    : client_key_(client_key), commit_requested_sequence_number_(0) {
+    : client_tag_(client_tag), commit_requested_sequence_number_(0) {
   DCHECK(metadata);
   DCHECK(metadata->has_client_tag_hash());
   metadata_.Swap(metadata);