Cleanup some dead code in blink::ImageBuffer and friends

Cleanup some dead code in blink::ImageBuffer and friends

The deprecatedBitmapForOverwrite() methods were still referenced but
never being called. This CL cleans that up.

BUG=551658
Committed: https://crrev.com/e0d003a62820bf5992f2e9ba9a0f10f3fff34576
Cr-Commit-Position: refs/heads/master@{#358558}

[Justin Novosad, 2015-11-04 22:32:44]

junov@chromium.org changed reviewers:
+ kbr@chromium.org

[Justin Novosad, 2015-11-04 22:32:44]

PTAL

[Justin Novosad, 2015-11-04 23:16:55]

On 2015/11/04 22:32:44, Justin Novosad wrote:
> PTAL

The mac fail is flake:
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=htt...

[Justin Novosad, 2015-11-05 18:17:04]

junov@chromium.org changed reviewers:
+ bajones@chromium.org

[Tom Hudson, 2015-11-05 20:08:55]

tomhudson@chromium.org changed reviewers:
+ tomhudson@chromium.org

[Tom Hudson, 2015-11-05 20:08:55]

Wow, that's a lot more dead code than I thought you'd found; only nit is 80
columns?

Waiting on landing this to update the patch you blocked for it.

[Justin Novosad, 2015-11-06 15:12:16]

kbr@: Review ping! You are the only OWNER of both modules/webgl and
platform/graphics

[bajones, 2015-11-07 20:19:31]

On 2015/11/06 15:12:16, Justin Novosad wrote:
> kbr@: Review ping! You are the only OWNER of both modules/webgl and
> platform/graphics

kbr@ is back on Monday, he's been out of the country. LGTM FWIW.

[jbroman, 2015-11-07 21:21:33]

junov: FYI, you are an owner of platform/graphics, so the review of that
directory doesn't require you to find another owner. Pre-commit owners checks
are done on the set "patch author + reviewers with lgtm".
(https://chromium.googlesource.com/chromium/tools/depot_tools/+/ff7840a8/presu...)

[Justin Novosad, 2015-11-08 21:53:55]

The CQ bit was checked by junov@chromium.org

[commit-bot: I haz the power, 2015-11-08 21:54:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1407133017/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1407133017/1

[commit-bot: I haz the power, 2015-11-08 23:12:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-08 23:13:40]

Patchset 1 (id:??) landed as
https://crrev.com/e0d003a62820bf5992f2e9ba9a0f10f3fff34576
Cr-Commit-Position: refs/heads/master@{#358558}

[Ken Russell (switch to Gerrit), 2015-11-10 03:21:37]

Sorry for not being around to review this. LGTM after the fact, assuming this
code path really can no longer be taken.