As in:

```diff
-Clock.fromNow = function(ms) {
+Clock.prototype.fromNow = function(ms) {
   ms = ms || 0;
+  ms += this.client.executeScript(function() {
+    return Date.now();
+  });
-  return new Date(Date.now() + ms);
+  return new Date(ms);
 }
```

?