Remove software paint path from WebTestProxy

Remove software paint path from WebTestProxy

BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=270959

[enne (OOO), 2014-05-14 21:42:14]

All layout tests should be force composited now.  Remove these old codepaths and
replace with CHECKs.

[danakj, 2014-05-15 14:29:35]

LGTM

https://codereview.chromium.org/284073002/diff/1/content/shell/renderer/test_...
File content/shell/renderer/test_runner/web_test_proxy.cc (right):

https://codereview.chromium.org/284073002/diff/1/content/shell/renderer/test_...
content/shell/renderer/test_runner/web_test_proxy.cc:515:
CHECK(web_widget_->isAcceleratedCompositingActive());
this could equivalently be a DCHECK i think, but whatevs

[enne (OOO), 2014-05-15 21:02:22]

+sky if you want to review this, since you looked at the follow-on patch here:
https://codereview.chromium.org/282083003/

[sky, 2014-05-15 22:38:50]

LGTM

[enne (OOO), 2014-05-15 22:48:36]

The CQ bit was checked by enne@chromium.org

[commit-bot: I haz the power, 2014-05-15 22:51:19]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/enne@chromium.org/284073002/1

[commit-bot: I haz the power, 2014-05-16 04:44:35]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  chromium_presubmit on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/chromium_presubmit/bu...)

[commit-bot: I haz the power, 2014-05-16 04:48:40]

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

[commit-bot: I haz the power, 2014-05-16 04:48:40]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/chromium_presubmit/bu...)

[jochen (gone - plz use gerrit), 2014-05-16 07:09:53]

lgtm

[commit-bot: I haz the power, 2014-05-16 08:05:02]

Change committed as 270959