Add some UMAs from Blink

Add some UMAs from Blink

Related CLs in Blink are following.
[HTMLImport] Add an Usecounter for the case imported document has stylesheets:
https://chromium.googlesource.com/chromium/blink/+/91dda90be4491a9eac3f989adab99c8988b
65a64
Add UseCounters for usage of -webkit-text:
https://chromium.googlesource.com/chromium/blink/+/cc28e1e7c4888777f0a4cf513098b23327c
7c571

BUG=523952
Committed: https://crrev.com/d094e1a1a3c6ba266c7c1389f35bed9c0b52b25d
Cr-Commit-Position: refs/heads/master@{#346547}

[yoichio, 2015-08-31 05:10:21]

yoichio@chromium.org changed reviewers:
+ isherman@chromium.org

[Ilya Sherman, 2015-08-31 23:53:45]

The CQ bit was checked by isherman@chromium.org

[Ilya Sherman, 2015-08-31 23:53:45]

lgtm

[commit-bot: I haz the power, 2015-08-31 23:54:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1307173006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1307173006/1

[commit-bot: I haz the power, 2015-09-01 01:18:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-01 01:19:25]

Patchset 1 (id:??) landed as
https://crrev.com/d094e1a1a3c6ba266c7c1389f35bed9c0b52b25d
Cr-Commit-Position: refs/heads/master@{#346547}