[V8] Use previous token location as EOS token location

[V8] Use previous token location as EOS token location

EOS token location is useless for users and messages.js are not ready for its location.
With this CL we use location of token before EOS for it.

LOG=Y
BUG=chromium:480652
R=yurys@chromium.org,yangguo@chromium.org

Committed: https://crrev.com/81afc9313ce84350bcba9f84b255a77e97cd3726
Cr-Commit-Position: refs/heads/master@{#28164}

[kozy, 2015-04-24 16:56:09]

Yury, please take a look!

[yurys, 2015-04-27 09:23:15]

https://codereview.chromium.org/1100993003/diff/1/src/messages.js
File src/messages.js (right):

https://codereview.chromium.org/1100993003/diff/1/src/messages.js#newcode404
src/messages.js:404: if (position - 1 > line_ends[upper]) {
I'd rather v8 highlighted position of the last token before EOS one. EOS is
oftentimes very confusing for the user as it gives little information about what
construction of the language is incomplete. Is there a way to provide position
of the token that goes before eos as the error position?

[kozy, 2015-04-28 18:42:17]

ptal!

[yurys, 2015-04-29 08:25:59]

lgtm, looks like this is the simplest way to get a meaningful location location
for the errors occurred at EOS.

[kozy, 2015-04-30 08:56:20]

Yang, please take a look.

[Yang, 2015-04-30 12:01:31]

On 2015/04/30 08:56:20, kozyatinskiy wrote:
> Yang, please take a look.

lgtm. But please watch out for parsing related performance regressions.

[kozy, 2015-04-30 12:21:20]

The CQ bit was checked by kozyatinskiy@chromium.org

[commit-bot: I haz the power, 2015-04-30 12:21:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1100993003/20001

[commit-bot: I haz the power, 2015-04-30 12:44:59]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-30 12:45:06]

Patchset 2 (id:??) landed as
https://crrev.com/81afc9313ce84350bcba9f84b255a77e97cd3726
Cr-Commit-Position: refs/heads/master@{#28164}

[Michael Achenbach, 2015-04-30 13:33:58]

machenbach@chromium.org changed reviewers:
+ machenbach@chromium.org

[Michael Achenbach, 2015-04-30 13:33:58]

[Sheriff] This might change layout test expectations:
http://build.chromium.org/p/client.v8/builders/V8-Blink%20Win/builds/3127
http://build.chromium.org/p/client.v8/builders/V8-Blink%20Mac/builds/2998

fast/events/window-onerror-04.html
virtual/pointerevent/fast/events/window-onerror-04.html

See archive:
https://storage.googleapis.com/chromium-layout-test-archives/V8-Blink_Mac/299...

Maybe also
svg/dom/SVGViewSpec.html
Not sure about that one.

Please submit a needsmanualrebaseline CL to blink or revert if this truly
changes expectations. We can wait until the builders fully finish to be sure.
Please keep me posted on this CL.

[kozy, 2015-04-30 13:42:39]

https://codereview.chromium.org/1115193002/

I've checked that this changes in test expectations are not errors and uploaded
CL which marks tests as needs manual rebaseline.

[Michael Achenbach, 2015-05-03 12:47:36]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1116233004/ by machenbach@chromium.org.

The reason for reverting is: [Sheriff] Speculative revert. This seems to block
the current roll:
https://codereview.chromium.org/1124463003/

This bisect also points at this CL:
https://codereview.chromium.org/1124523002/

Please prepare the chromium side tests before a reland..