Copy JSSyntaxRegExp from frog.

Copy JSSyntaxRegExp from frog.

Committed: https://code.google.com/p/dart/source/detail?r=4440

[ahe, 2012-02-20 16:13:49]

Total: 3084 tests                              
 * 184 tests will be skipped
 * 1 tests are expected to be flaky but not crash
 * 1766 tests are expected to pass
 * 443 tests are expected to fail that we won't fix
 * 683 tests are expected to fail that we should fix
 * 2 tests are expected to crash that we should fix
 * 0 tests are allowed to timeout

[kasperl, 2012-02-21 07:35:17]

LGTM.

https://chromiumcodereview.appspot.com/9423042/diff/1/dart/frog/leg/lib/js_he...
File dart/frog/leg/lib/js_helper.dart (right):

https://chromiumcodereview.appspot.com/9423042/diff/1/dart/frog/leg/lib/js_he...
dart/frog/leg/lib/js_helper.dart:804: checkNull(value);
Would it be simpler to rewrite some of these to do a positive is test instead?
Something like:

   if (value is String) return value;
   throw new IllegalArgumentException(value);

That way you don't need the explicit null check.

[ngeoffray, 2012-02-21 12:18:29]

LGTM

[ahe, 2012-02-22 09:14:38]

Hi Nicolas and Kasper,

Thank you for taking a look. I'll follow up on your suggestions in a new CL.

Cheers,
Peter