anchor.diff:  SendPortSync _jsGlobalize = null;
   SendPortSync _jsInvalidate = null;
   
  -// Initialize bootstrap code and ports.
  +// Initializes bootstrap code and ports.
   void _initialize() {
     if (_jsPortSync != null) return;
     _inject(_JS_BOOTSTRAP);
  
positive.code:   // Overridable initialization on first use hook.
    ProxiedReferenceTable.prototype._initialize = function () {}
  
    // Enter a new scope for this table.
    ProxiedReferenceTable.prototype.enterScope = function() {
      this._initializeOnce();
      this.scopeIndices.push(this.handleStack.length);
    }
    
    // Invalidate all non-global IDs in the current scope and
    // exit the current scope.
    ProxiedReferenceTable.prototype.exitScope = function() {
      var start = this.scopeIndices.pop();
  
negative.code:     _handleStack.removeRange(start, _handleStack.length - start);
    }
  
    // Converts an ID to a global.
    globalize(id) => _globalIds.add(id);
  
    // Invalidates an ID.
    invalidate(id) {
      var old = _registry[id];
      _globalIds.remove(id);
  