Check for the case where previousNode fails in sanitization. Can happen with object tags

Check for the case where previousNode fails in sanitization. Can happen with object tags

BUG=
R=sra@google.com

Committed: https://github.com/dart-lang/sdk/commit/c5acca2ff0080fa7c3db61de74dc58864fa806dd

[Alan Knight, 2016-03-23 23:13:09]

alanknight@google.com changed reviewers:
+ sra@google.com

[sra1, 2016-03-25 17:20:12]

LGTM.

Do you have a test?

I'm a bit worried that the 'restart' is recursion.

https://codereview.chromium.org/1825373004/diff/1/tools/dom/src/Validators.dart
File tools/dom/src/Validators.dart (right):

https://codereview.chromium.org/1825373004/diff/1/tools/dom/src/Validators.da...
tools/dom/src/Validators.dart:170: while (!identical(child, null)) {
!= null is fine - null as an explicit argument is always handled specially. If
your are still nervous:

null != child

the receiver is null so it has known behaviour.

https://codereview.chromium.org/1825373004/diff/1/tools/dom/src/Validators.da...
tools/dom/src/Validators.dart:177: // child appears bad, remove it and restart
the traversal without it.
Say why a restart is necessary instead of just removing the node.

[Alan Knight, 2016-03-25 18:10:46]

PTAL.

Unfortunately I could not reproduce the problem standalone - the only thing that
reproduces it was an in an internal test where dart2js compiled previousNode to
go through an interceptor.

https://codereview.chromium.org/1825373004/diff/1/tools/dom/src/Validators.dart
File tools/dom/src/Validators.dart (right):

https://codereview.chromium.org/1825373004/diff/1/tools/dom/src/Validators.da...
tools/dom/src/Validators.dart:170: while (!identical(child, null)) {
On 2016/03/25 17:20:12, sra1 wrote:
> != null is fine - null as an explicit argument is always handled specially. If
> your are still nervous:
> 
> null != child
> 
> the receiver is null so it has known behaviour.

OK, just being extremely paranoid. Made it null != child

https://codereview.chromium.org/1825373004/diff/1/tools/dom/src/Validators.da...
tools/dom/src/Validators.dart:177: // child appears bad, remove it and restart
the traversal without it.
On 2016/03/25 17:20:12, sra1 wrote:
> Say why a restart is necessary instead of just removing the node.

Added comment. Rewrote it to not be recursive.

[Alan Knight, 2016-04-28 19:51:50]

Description was changed from

==========
Check for the case where previousNode fails in sanitization. Can happen with
object tags

BUG=
==========

to

==========
Check for the case where previousNode fails in sanitization. Can happen with
object tags

BUG=
R=sra@google.com

Committed:
https://github.com/dart-lang/sdk/commit/c5acca2ff0080fa7c3db61de74dc58864fa806dd
==========

[Alan Knight, 2016-04-28 19:51:51]

Committed patchset #2 (id:20001) manually as
c5acca2ff0080fa7c3db61de74dc58864fa806dd (presubmit successful).