Remove CONST_LEGACY VariableMode

src/parsing/parser.cc

Index: src/parsing/parser.cc
diff --git a/src/parsing/parser.cc b/src/parsing/parser.cc
index 1d19e42c9e7ccb6810fdda788cd1d17d9dbc3232..0d9b2bbb4fa22a5cf1659e4f101d80a0d9222bd2 100644
--- a/src/parsing/parser.cc
+++ b/src/parsing/parser.cc
@@ -1988,7 +1988,7 @@ Variable* Parser::Declare(Declaration* declaration,
                           DeclarationDescriptor::Kind declaration_kind,
                           VariableMode mode, InitializationFlag init, bool* ok,
                           Scope* scope) {
-  DCHECK(IsDeclaredVariableMode(mode) && mode != CONST_LEGACY);
+  DCHECK(IsDeclaredVariableMode(mode));
 
   VariableProxy* proxy = declaration->proxy();
   DCHECK(proxy->raw_name() != NULL);
@@ -2049,8 +2049,7 @@ Variable* Parser::Declare(Declaration* declaration,
       } else {
         // The name was declared in this scope before; check for conflicting
         // re-declarations. We have a conflict if either of the declarations
-        // is not a var (in script scope, we also have to ignore legacy const
-        // for compatibility). There is similar code in runtime.cc in the
+        // is not a var. There is similar code in runtime.cc in the
         // Declare functions. The function CheckConflictingVarDeclarations
         // checks for var and let bindings from different scopes whereas this
         // is a check for conflicting declarations within the same scope. This