Fix a bug in delete for lookup slots.

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 772eb8f9054c3121447068516d23ba7915f98c94..95213d1ebd97ad8332c7982e068a142b187eb415 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -3689,19 +3689,18 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
         if (prop != NULL) {
           VisitForStackValue(prop->obj());
           VisitForStackValue(prop->key());
+          __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
         } else if (var->is_global()) {
           __ push(GlobalObjectOperand());
           __ push(Immediate(var->name()));
+          __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
         } else {
-          // Non-global variable.  Call the runtime to look up the context
-          // where the variable was introduced.
+          // Non-global variable.  Call the runtime to delete from the
+          // context where the variable was introduced.
           __ push(context_register());
           __ push(Immediate(var->name()));
-          __ CallRuntime(Runtime::kLookupContext, 2);
-          __ push(eax);
-          __ push(Immediate(var->name()));
+          __ CallRuntime(Runtime::kDeleteContextSlot, 2);
         }
-        __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
         context()->Plug(eax);
       }
       break;