Further code review changes for issue 8341027.

client/html/src/DOMWrapperBase.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class DOMWrapperBase {
   final _ptr;
 
   DOMWrapperBase._wrap(this._ptr) {
-        // We should never be creating duplicate wrappers.
-        assert(_ptr.dartObjectLocalStorage === null);
-        _ptr.dartObjectLocalStorage = this;
+    if (this._ptr == null) return;
+    // We should never be creating duplicate wrappers.

[Jacob, 2011/10/27 21:01:27]

because this is on the hot path for every time any wrapper is created, add a
second zero arg named constructor instead of adding the if.
The second constructor could actually be const which should allow
EmptyCSSStyleDeclaration to also be const and now that i think about it then
you'd be able to enable reuse of the EmptyCSSStyleDeclaration without caching
it.
e.g.

const DOMWrapperBase._empty() : _ptr = null;


then write 
const EmptyCSSStyleDeclaration();
instead of
new EmptyCSSStyleDeclaration()

[nweiz, 2011/10/27 21:20:35]

Done.

+    assert(_ptr.dartObjectLocalStorage === null);
+    _ptr.dartObjectLocalStorage = this;
   }
 }