Move lang-code checking for case-mapping to C++ from JS

Move lang-code checking for case-mapping to C++ from JS

Move the language code checking for 4 languages requiring
special case mapping to C++ from JavaScript.

This is a speculative fix for crashes reported from Windows and
Mac Chrome canary builds when icu-case-mapping is enabled by
default. (see crbug.com/676643)

In addition, tighten up comparision operators in a couple of
places in i18n.js (=== and !== instead of == and !=).

BUG=v8:4477, v8:4476, chromium:676643
TEST=test262/{built-ins,intl402}/Strings/*, webkit/fast/js/*,
     mjsunit/string-case, intl/general/case*

Review-Url: https://codereview.chromium.org/2621393002
Cr-Commit-Position: refs/heads/master@{#42246}
Committed: https://chromium.googlesource.com/v8/v8/+/db883422c88d1c9c2b0c4991ccc8197d07bc0ba6

[jungshik at Google, 2017-01-11 19:00:44]

jshin@chromium.org changed reviewers:
+ littledan@chromium.org

[jungshik at Google, 2017-01-11 19:00:45]

Hi Dan, 

Can you take a look?

[Dan Ehrenberg, 2017-01-11 19:09:20]

lgtm

Code looks good to me. Would be nicer with a regression test, but if we can't
find one, this seems OK to land as is.

[jungshik at Google, 2017-01-11 19:11:22]

https://codereview.chromium.org/2621393002/diff/20001/src/runtime/runtime-i18...
File src/runtime/runtime-i18n.cc (left):

https://codereview.chromium.org/2621393002/diff/20001/src/runtime/runtime-i18...
src/runtime/runtime-i18n.cc:1155: CONVERT_ARG_HANDLE_CHECKED(SeqOneByteString,
lang, 2);
From i18n.js, a string "literal" ( e.g. "el", "tr", "az", "lt" ) is passed and I
assumed that it'd be SeqOneByteString. However, my analysis of minidump from
Windows Chrome canary builds on Windows indicates that the above check fails. 

So, in this CL, I'm not relying on that assumption any more by moving language
code check from i18n.js to runtime-i18n.cc.

[jungshik at Google, 2017-01-11 19:12:49]

The CQ bit was checked by jshin@chromium.org

[commit-bot: I haz the power, 2017-01-11 19:13:01]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-11 19:42:50]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1484161969494700,
"parent_rev": "84d3abe390f9c44427e3be4a4f0d6b8adc2a0614", "commit_rev":
"db883422c88d1c9c2b0c4991ccc8197d07bc0ba6"}

[commit-bot: I haz the power, 2017-01-11 19:42:54]

Description was changed from

==========
Move lang-code checking for case-mapping to C++ from JS

Move the language code checking for 4 languages requiring
special case mapping to C++ from JavaScript.

This is a speculative fix for crashes reported from Windows and
Mac Chrome canary builds when icu-case-mapping is enabled by
default. (see crbug.com/676643)

In addition, tighten up comparision operators in a couple of
places in i18n.js (=== and !== instead of == and !=).

BUG=v8:4477, v8:4476, chromium:676643
TEST=test262/{built-ins,intl402}/Strings/*, webkit/fast/js/*,
     mjsunit/string-case, intl/general/case*
==========

to

==========
Move lang-code checking for case-mapping to C++ from JS

Move the language code checking for 4 languages requiring
special case mapping to C++ from JavaScript.

This is a speculative fix for crashes reported from Windows and
Mac Chrome canary builds when icu-case-mapping is enabled by
default. (see crbug.com/676643)

In addition, tighten up comparision operators in a couple of
places in i18n.js (=== and !== instead of == and !=).

BUG=v8:4477, v8:4476, chromium:676643
TEST=test262/{built-ins,intl402}/Strings/*, webkit/fast/js/*,
     mjsunit/string-case, intl/general/case*

Review-Url: https://codereview.chromium.org/2621393002
Cr-Commit-Position: refs/heads/master@{#42246}
Committed:
https://chromium.googlesource.com/v8/v8/+/db883422c88d1c9c2b0c4991ccc8197d07b...
==========

[commit-bot: I haz the power, 2017-01-11 19:42:55]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/db883422c88d1c9c2b0c4991ccc8197d07b...

[jungshik at Google, 2017-01-11 21:28:16]

On 2017/01/11 19:09:20, Dan Ehrenberg wrote:
> lgtm
> 
> Code looks good to me. Would be nicer with a regression test, but if we can't
> find one, this seems OK to land as is.

I'm afraid it is not possible in v8 alone. If it were possible, it'd have been
caught by multiple tests on Windows trybots. 
I'm setting up a Windows build environment and plan to try reproducing it in
Chrome on Windows. It'd be tricky because I failed to get 
a script source out of any of minidump files from Windows. It could be as simple
as calling toLocale{Upper,Lower}. I may or may not have to set Chrome's UI
locale to one of {el,tr,az,lt}.