Revert of Make 2D canvas smarter about chosing whether or not to use GPU acceleration

Revert of Make 2D canvas smarter about chosing whether or not to use GPU acceleration (patchset #2 id:20001 of https://codereview.chromium.org/1367683002/ )

Reason for revert:
Patch has test failures

Original issue's description:
> Make 2D canvas smarter about chosing whether or not to use GPU acceleration
>
> The CL takes advantage of the fact that canvas rendering is deferred
> to defer the decision of whether or not a canvas should be
> GPU-accelerated. The decision is made based on the conditions
> under which a canvas is flushed for the first time. For example,
> if the purpose of the first flush is to perform a readback, then
> GPU-acceleration will be disabled for the canvas in order to avoid
> reading GPU memory into RAM, which is known to be a slow path.
>
> BUG=265849
> TBR=senorblanco@chromium.org, kbr@chromium.org
> NOTRY=true
>
> Committed: https://crrev.com/9ac9c385c8f55f826c42e1f3a56cf66600b9e934
> Cr-Commit-Position: refs/heads/master@{#350655}

TBR=kbr@chromium.org,senorblanco@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=265849
Committed: https://crrev.com/e8cac159f27bb9a24eca106cdea07abdf421f29c
Cr-Commit-Position: refs/heads/master@{#350673}

[Justin Novosad, 2015-09-24 21:38:03]

Created Revert of Make 2D canvas smarter about chosing whether or not to use GPU
acceleration

[commit-bot: I haz the power, 2015-09-24 21:39:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1361043003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1361043003/1

[commit-bot: I haz the power, 2015-09-24 21:41:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-24 21:42:23]

Patchset 1 (id:??) landed as
https://crrev.com/e8cac159f27bb9a24eca106cdea07abdf421f29c
Cr-Commit-Position: refs/heads/master@{#350673}