Check for null selectors when looping in findBestRuleSetAndAdd

Check for null selectors when looping in findBestRuleSetAndAdd.

This is necessary because a relation() of SubSelector does not in all cases guarantee that tagHistory() is non-NULL.

This happens in particular for this selector:

af|inputtext:focus::content { ... }

BUG=358475
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=170611

[ojan, 2014-04-01 19:49:24]

test?

[chrishtr, 2014-04-01 20:43:45]

Added test.

[ojan, 2014-04-01 21:20:49]

lgtm

Please add the FIXME and fix the test before committing.

https://codereview.chromium.org/218403012/diff/40001/LayoutTests/fast/css/inp...
File LayoutTests/fast/css/inputtext-crash.html (right):

https://codereview.chromium.org/218403012/diff/40001/LayoutTests/fast/css/inp...
LayoutTests/fast/css/inputtext-crash.html:1: <style>
Nit: add doctype. We default to running all tests in standards mode.

Also, as is, this will run as a pixel test with a render tree dump. You need:
if (window.testRunner)
    testRunner.dumpAsText().

Also, you appear to be missing the -expected.txt file.

https://codereview.chromium.org/218403012/diff/40001/Source/core/css/RuleSet.cpp
File Source/core/css/RuleSet.cpp (right):

https://codereview.chromium.org/218403012/diff/40001/Source/core/css/RuleSet....
Source/core/css/RuleSet.cpp:183: if (it)
This makes me sad. I'm OK with the patch to fix the P1 bug, but can we add a
FIXME to make inputtext not do crazy so that we can keep the system simpler and
not need these null-checks.

[chrishtr, 2014-04-01 21:27:58]

https://codereview.chromium.org/218403012/diff/40001/LayoutTests/fast/css/inp...
File LayoutTests/fast/css/inputtext-crash.html (right):

https://codereview.chromium.org/218403012/diff/40001/LayoutTests/fast/css/inp...
LayoutTests/fast/css/inputtext-crash.html:1: <style>
On 2014/04/01 21:20:50, ojan wrote:
> Nit: add doctype. We default to running all tests in standards mode.
> 
> Also, as is, this will run as a pixel test with a render tree dump. You need:
> if (window.testRunner)
>     testRunner.dumpAsText().
> 
> Also, you appear to be missing the -expected.txt file.

Done.

https://codereview.chromium.org/218403012/diff/40001/Source/core/css/RuleSet.cpp
File Source/core/css/RuleSet.cpp (right):

https://codereview.chromium.org/218403012/diff/40001/Source/core/css/RuleSet....
Source/core/css/RuleSet.cpp:183: if (it)
On 2014/04/01 21:20:50, ojan wrote:
> This makes me sad. I'm OK with the patch to fix the P1 bug, but can we add a
> FIXME to make inputtext not do crazy so that we can keep the system simpler
and
> not need these null-checks.

Done.

[chrishtr, 2014-04-01 21:28:04]

The CQ bit was checked by chrishtr@chromium.org

[commit-bot: I haz the power, 2014-04-01 22:42:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/chrishtr@chromium.org/218403012/50005

[commit-bot: I haz the power, 2014-04-01 23:52:20]

Change committed as 170611