Disable the thread-safe MQ parser for main thread

Disable the thread-safe MQ parser for main thread

This reverts commit d1eea2e66e64c3c019885ad7e94933aa0fc05576.
On top of that, this CL makes sure that only the preloader uses the thread safe MQ parser. That's in order to reduce the risk of breaking content when introducing the new MQ parser.

BUG=358078
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=170494

[Yoav Weiss, 2014-03-31 11:06:52]

Since we've discovered some potential compatibility issues with the thread safe
MQ parser, we may need to disable it for main-thread MQ evaluation *on the M35
branch*.

[eseidel, 2014-03-31 15:45:13]

lgtm, but you'll need a Merge-Approved from the M35 release manager (who I think
is kareng).

You ran whatever MQ tests we have, correct? to make sure that the main thread MQ
parser now correctly parses comment, etc?

[Yoav Weiss, 2014-03-31 16:43:46]

On 2014/03/31 15:45:13, eseidel wrote:
> lgtm, but you'll need a Merge-Approved from the M35 release manager (who I
think
> is kareng).
> 
> You ran whatever MQ tests we have, correct? to make sure that the main thread
MQ
> parser now correctly parses comment, etc?

Unfortunately, the MQ tests fail on the Bison Parser (since it is not fully
standard compliant in its own way).
I can get the tests to run on the Bison parser, while disabling the ones where
it fails.

[eseidel, 2014-03-31 17:13:24]

I see.  I'm OK with us understanding that BisonCSSParser is broken (fails some
tests) as it's the devil we (and web authors know) and I'd rather keep it for
M35 since there may yet be breaks we don't understand from the MQ parser
re-write.

Thanks again for taking care of this.  So long as you've at least tested
manually, I'm OK with this.

[eseidel, 2014-03-31 17:14:17]

I've confirmed that kareng is the release owner for M35, so it's her
Merge-Approved which you'll need.  She's CC'd on the bug.

[Yoav Weiss, 2014-03-31 17:30:01]

On 2014/03/31 17:13:24, eseidel wrote:
> I see.  I'm OK with us understanding that BisonCSSParser is broken (fails some
> tests) as it's the devil we (and web authors know) and I'd rather keep it for
> M35 since there may yet be breaks we don't understand from the MQ parser
> re-write.
Switched the tests to use BisonCSSParser and commented out a failing one.

> 
> Thanks again for taking care of this.  So long as you've at least tested
> manually, I'm OK with this.

[eseidel, 2014-03-31 21:50:24]

lgtm to land on trunk.  We'll land on trunk first, let it bake in canary for a
day or two and then merge to the branch.

[Yoav Weiss, 2014-03-31 21:53:34]

The CQ bit was checked by yoav@yoav.ws

[commit-bot: I haz the power, 2014-03-31 21:53:39]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/yoav@yoav.ws/219183002/20001

[commit-bot: I haz the power, 2014-04-01 00:08:46]

Change committed as 170494