Add assertion about module scopes to Scope::ContextChainLength.

R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/14513002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14459 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/scopes.cc

@@ -727,8 +727,9 @@ int Scope::ContextChainLength(Scope* scope) {
   for (Scope* s = this; s != scope; s = s->outer_scope_) {
     ASSERT(s != NULL);  // scope must be in the scope chain
     if (s->is_with_scope() || s->num_heap_slots() > 0) n++;
-    // Catch scopes always have heap slots.
+    // Catch and module scopes always have heap slots.
     ASSERT(!s->is_catch_scope() || s->num_heap_slots() > 0);
+    ASSERT(!s->is_module_scope() || s->num_heap_slots() > 0);
   }
   return n;
 }