Merge acceleratedCompositingForFixedRootBackground into preferCompositingToLCDText

Merge acceleratedCompositingForFixedRootBackground into preferCompositingToLCDText

This removes the acceleratedCompositingForFixedRootBackground setting
and makes the WebSetting setter a no-op. Any code that checked for
this setting is replaced with a check for
preferCompositingToLCDTextEnabled instead.

R=abarth, vollick@chromium.org
BUG=365851
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180431

[abarth-chromium, 2014-08-18 00:34:01]

LGTM

[danakj, 2014-08-18 06:45:29]

The CQ bit was checked by danakj@chromium.org

[commit-bot: I haz the power, 2014-08-18 06:45:38]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/danakj@chromium.org/479893002/1

[commit-bot: I haz the power, 2014-08-18 07:22:20]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/23151)

[commit-bot: I haz the power, 2014-08-18 07:52:48]

Committed patchset #1 (1) as 180431