Add argument error for int.parse(null).

Add argument error for int.parse(null).

Slightly tweak _tryParseSmi to generate slightly less code.

BUG= http://dartbug.com/17774
R=fschneider@google.com

Committed: https://code.google.com/p/dart/source/detail?r=40373

[Lasse Reichstein Nielsen, 2014-09-17 12:12:59]

lrn@google.com changed reviewers:
+ fschneider@google.com

[Florian Schneider, 2014-09-17 12:35:49]

lgtm

[Lasse Reichstein Nielsen, 2014-09-17 12:51:30]

Committed patchset #1 (id:1) manually as 40373 (presubmit successful).

[srdjan, 2014-09-17 15:13:52]

srdjan@google.com changed reviewers:
+ srdjan@google.com

[srdjan, 2014-09-17 15:13:53]

https://codereview.chromium.org/581593002/diff/1/runtime/lib/integers_patch.dart
File runtime/lib/integers_patch.dart (right):

https://codereview.chromium.org/581593002/diff/1/runtime/lib/integers_patch.d...
runtime/lib/integers_patch.dart:65: if (identical(source, null)) throw new
ArgumentError(source);
Please explain why you are using identical instead of ==.

[Lasse Reichstein Nielsen, 2014-09-17 15:28:04]

https://codereview.chromium.org/581593002/diff/1/runtime/lib/integers_patch.dart
File runtime/lib/integers_patch.dart (right):

https://codereview.chromium.org/581593002/diff/1/runtime/lib/integers_patch.d...
runtime/lib/integers_patch.dart:65: if (identical(source, null)) throw new
ArgumentError(source);
Ack, a silly attempt to see if it made any difference (it didn't), but I forgot
to roll it back.
I'll undo that.