Add tests to make sure gpu blacklist actually block gpu features.

Add tests to make sure gpu blacklist actually block gpu features.

(Retry after a fix.)

The general idea is to use jbates's newly added tracing: if a feature is blacklisted, we check the tracing data to make sure gpu process hasn't launched. 

BUG=101222
TEST=browser_tests 
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=109740

[Zhenyao Mo, 2011-11-10 00:54:42]

Sorry for this, but the Cl you reviewed yesterday was reverted due to a Win
compilation fail.  This CL contains the original CL plus the fix.

To make the review easier, I uploaded the original CL as patch 1, and the
updated CL with the fix as patch 2, so you can easily see where the changes are.

Please have another look.

[jbates, 2011-11-10 01:06:18]

lgtm

[Zhenyao Mo, 2011-11-11 00:23:43]

Al: ping.

[apatrick_chromium, 2011-11-11 19:52:52]

LGTM

[commit-bot: I haz the power, 2011-11-11 20:04:52]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/zmo@chromium.org/8510032/10001

[commit-bot: I haz the power, 2011-11-11 21:09:17]

Try job failure for 8510032-10001 (retry) on mac_rel for step "compile" (clobber
build).
It's a second try, previously, step "compile" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_rel&nu...