Experimental tuning for DirectWrite font cache.

Experimental tuning for DirectWrite font cache.
I don't expect significant improvment with such little tuning, but want to test it with more user base to see the direction.

Here is the summary of experiments I did on my machine.
I have total of 454 font files on my system.

Percent of file content cached: 85%,
File Size: 35MB
Cached fonts: 422 (92%)

Percent of file content cached: 75%
File Size: 29MB
Cached fonts 335 (73%)

Percent of file content cached: 65%
File Size: 24MB
Cached fonts: 240 (52%)

Percent of file content cached: 60%
File Size: 23MB
Cached fonts 236 (51%)

Percent of file content cached: 50%
File Size: 13MB
Cached fonts 231 (50%)

BUG=449687
R=cpu,scottmg,ananta

Committed: https://crrev.com/cddd0218013b6611389c184050fe6a4daacc778e
Cr-Commit-Position: refs/heads/master@{#313020}

[scottmg, 2015-01-23 01:22:23]

I guess it's ok to play around with, so lgtm, but is there some way we could
gather these numbers in the field rather than just your machine?

[Shrikant Kelkar, 2015-01-23 01:25:45]

On 2015/01/23 01:22:23, scottmg wrote:
> I guess it's ok to play around with, so lgtm, but is there some way we could
> gather these numbers in the field rather than just your machine?

Yes, that was the intention. Gather from field. I posted numbers from my machine
just for reference.

[scottmg, 2015-01-23 01:36:08]

On 2015/01/23 01:25:45, Shrikant Kelkar wrote:
> On 2015/01/23 01:22:23, scottmg wrote:
> > I guess it's ok to play around with, so lgtm, but is there some way we could
> > gather these numbers in the field rather than just your machine?
> 
> Yes, that was the intention. Gather from field. I posted numbers from my
machine
> just for reference.

We're only going to get UMA for 60%/30M now though right? I was wondering if
there was something we could do to do a better survey across values in the
field. I'm not sure exactly what it should look like though.

[Shrikant Kelkar, 2015-01-23 01:46:21]

On 2015/01/23 01:36:08, scottmg wrote:
> On 2015/01/23 01:25:45, Shrikant Kelkar wrote:
> > On 2015/01/23 01:22:23, scottmg wrote:
> > > I guess it's ok to play around with, so lgtm, but is there some way we
could
> > > gather these numbers in the field rather than just your machine?
> > 
> > Yes, that was the intention. Gather from field. I posted numbers from my
> machine
> > just for reference.
> 
> We're only going to get UMA for 60%/30M now though right? I was wondering if
> there was something we could do to do a better survey across values in the
> field. I'm not sure exactly what it should look like though.

One way I can think of is to use fieldtrial, I have no idea how to.. but will
explore.

[cpu_(ooo_6.6-7.5), 2015-01-24 00:00:29]

lgtm

[cpu_(ooo_6.6-7.5), 2015-01-24 00:00:34]

The CQ bit was checked by cpu@chromium.org

[commit-bot: I haz the power, 2015-01-24 00:01:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869003002/20001

[commit-bot: I haz the power, 2015-01-24 01:40:17]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-24 01:40:18]

Try jobs failed on following builders:
  win_chromium_x64_rel_ng on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[Shrikant Kelkar, 2015-01-24 01:50:31]

The CQ bit was checked by shrikant@chromium.org

[commit-bot: I haz the power, 2015-01-24 01:51:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869003002/40001

[commit-bot: I haz the power, 2015-01-24 03:54:43]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-24 03:54:44]

Try jobs failed on following builders:
  win_chromium_x64_rel_ng on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[Shrikant Kelkar, 2015-01-24 15:28:42]

The CQ bit was checked by shrikant@chromium.org

[commit-bot: I haz the power, 2015-01-24 15:29:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869003002/40001

[commit-bot: I haz the power, 2015-01-24 15:29:57]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-01-24 15:31:03]

Patchset 3 (id:??) landed as
https://crrev.com/cddd0218013b6611389c184050fe6a4daacc778e
Cr-Commit-Position: refs/heads/master@{#313020}