Revert of Revert of Enable display list 2D canvas by default

Revert of Revert of Enable display list 2D canvas by default (patchset #1 id:1 of https://codereview.chromium.org/824063002/)

Reason for revert:
The reason for the revert was resolved: crbug.com/445051

Original issue's description:
> Revert of Enable display list 2D canvas by default (patchset #1 id:1 of https://codereview.chromium.org/818443002/)
>
> Reason for revert:
> Breaks devtools highlight on hidpi screens. See crbug.com/445051.
>
> Original issue's description:
> > Enable display list 2D canvas by default
> >
> > With this change, display list 2D canvas will become enabled by
> > default in Chrome. Content shell with --dump-render-tree will
> > continue to have display lists disabled by default.
> > Currently, having display lists enabled in blink means
> > that display lists will be used whenever 2d canvases would
> > not be GPU-accelerated.
> >
> > BUG=386601
> >
> > Committed: https://crrev.com/1546f423005338aac5961415bbfc48c61dc183ae
> > Cr-Commit-Position: refs/heads/master@{#309453}
>
> TBR=avi@chromium.org,junov@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=386601
>
> Committed: https://crrev.com/5b6f044b9bc14af9b265746d31db547be18d9dbb
> Cr-Commit-Position: refs/heads/master@{#309635}

TBR=avi@chromium.org,pfeldman@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=386601
Committed: https://crrev.com/5d6c61887aebd1689283ceb0b01d0e1b9f431740
Cr-Commit-Position: refs/heads/master@{#310146}

[Justin Novosad, 2015-01-06 21:10:30]

Created Revert of Revert of Enable display list 2D canvas by default

[commit-bot: I haz the power, 2015-01-06 21:10:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/837773003/1

[commit-bot: I haz the power, 2015-01-06 21:11:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-06 21:12:57]

Patchset 1 (id:??) landed as
https://crrev.com/5d6c61887aebd1689283ceb0b01d0e1b9f431740
Cr-Commit-Position: refs/heads/master@{#310146}