Fix C++ compilation issue

TBR=marja@chromium.org
BUG=

Review URL: https://codereview.chromium.org/199743006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19977 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/preparser.h

@@ -1626,7 +1626,7 @@ typename Traits::Type::Expression ParserBase<Traits>::ParseAssignmentExpression(
     return expression;
   }
 
-  if (!IsValidLeftHandSide(expression)) {
+  if (!this->IsValidLeftHandSide(expression)) {
     this->ReportMessageAt(lhs_location, "invalid_lhs_in_assignment", true);
     *ok = false;
     return this->EmptyExpression();