Remove not used mem_root argument from build_clone(), get_copy() and get_item_copy()

TODO:
- Make get_thd_memroot() inline
  - To do this, we need to reduce dependence of include files, especially
    so that sql_class.h is not depending in item.h

1 files changed, 4 insertions, 4 deletions

diff --git a/sql/item_row.cc b/sql/item_row.cc
index 9c029b16292..eae88cd2e6e 100644
--- a/sql/item_row.cc
+++ b/sql/item_row.cc
@@ -163,15 +163,15 @@ void Item_row::bring_value()
 }
 
 
-Item* Item_row::build_clone(THD *thd, MEM_ROOT *mem_root)
+Item* Item_row::build_clone(THD *thd)
 {
-  Item_row *copy= (Item_row *) get_copy(thd, mem_root);
+  Item_row *copy= (Item_row *) get_copy(thd);
   if (!copy)
     return 0;
-  copy->args= (Item**) alloc_root(mem_root, sizeof(Item*) * arg_count);
+  copy->args= (Item**) alloc_root(thd->mem_root, sizeof(Item*) * arg_count);
   for (uint i= 0; i < arg_count; i++)
   {
-    Item *arg_clone= args[i]->build_clone(thd, mem_root);
+    Item *arg_clone= args[i]->build_clone(thd);
     if (!arg_clone)
       return 0;
     copy->args[i]= arg_clone;