Revamp style resolver stats

Revamp style resolver stats

Instead of the stats being behind a bunch of macros and needing to be enabled
at compile time we make them runtime enabled and expose them through
Internals.

With this new infrastructure you can do internals.setStyleResolverStatsEnabled(true) 
in a test and then trigger a recalc and finally call internals.styleResolverStatsTotalsReport()
to get a text dump of lots of interesting statistics. We can then land tests that dump
these statistics to track improvements or regressions in the matched property cache
or style sharing logic.

We might also consider adding a runtime flag to print out this information, or even making
it so that the web inspector could expose how much style sharing vs actual rule matching
a given page is doing.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=161894

[leviw_travelin_and_unemployed, 2013-10-23 01:37:42]

I like the idea of having this on in general without the DOM crawl. This is fine
to start with. LGTM.

[commit-bot: I haz the power, 2013-10-23 01:41:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/esprehn@chromium.org/34623009/2

[ojan, 2013-10-23 02:02:49]

It's kind of a bummer that we ship this to users.

Also, it's kind of a bummer not to be able to see what the ideal sharing
percentage would be.

I'm not necessarily opposed to this change...just...sad.

[esprehn, 2013-10-23 02:30:40]

On 2013/10/23 02:02:49, ojan wrote:
> It's kind of a bummer that we ship this to users.
> 
> Also, it's kind of a bummer not to be able to see what the ideal sharing
> percentage would be.

What do you mean?

> 
> I'm not necessarily opposed to this change...just...sad.

Keeping lots of code behind ifdefs is not good for maintainability. We also need
some way to write tests. :/ 

I think it's actually good to ship this to users, we should get it connected to
the inspector so developers can see how often we match their CSS rules vs just
sharing style. It makes as much as a 50% difference in perf.

[commit-bot: I haz the power, 2013-10-23 02:31:23]

Sorry for I got bad news for ya.
Compile failed with a clobber build on mac_layout.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_layout...
Your code is likely broken or HEAD is junk. Please ensure your
code is not broken then alert the build sheriffs.
Look at the try server FAQ for more details.

[commit-bot: I haz the power, 2013-10-23 02:38:39]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/esprehn@chromium.org/34623009/200001

[commit-bot: I haz the power, 2013-10-23 05:05:41]

Retried try job too often on mac_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_blink_...

[commit-bot: I haz the power, 2013-10-23 07:06:41]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/esprehn@chromium.org/34623009/200001

[commit-bot: I haz the power, 2013-10-23 09:58:07]

Retried try job too often on mac_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_blink_...

[esprehn, 2013-10-31 18:29:53]

On 2013/10/23 09:58:07, I haz the power (commit-bot) wrote:
> Retried try job too often on mac_blink_rel for step(s) webkit_tests
>
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_blink_...

The mac bot was having trouble with the test being flaky. I've removed the test
for now. I think it's good to land this patch and make it easier to add stats in
the future, expose them in the inspector and debug tests (you can now easily
print style sharing and property cache data in a test when debugging).

[commit-bot: I haz the power, 2013-10-31 19:31:32]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/esprehn@chromium.org/34623009/430001

[commit-bot: I haz the power, 2013-10-31 22:53:16]

Retried try job too often on mac_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_blink_...

[commit-bot: I haz the power, 2013-11-13 07:53:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/esprehn@chromium.org/34623009/560001

[commit-bot: I haz the power, 2013-11-13 09:05:05]

Change committed as 161894