Make deferred image decoding default to on.

Make deferred image decoding default to on.

It's always enabled with impl-side painting. And impl-side painting is
now always on for blink (we recently removed the last hold-out layout
tests).

https://codereview.chromium.org/1179653004/ removes it as an option on
the chromium side and always gives true to
setDeferredImageDecodingEnabled.

R=schenney@chromium.org
BUG=413479
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196969

[danakj, 2015-06-10 22:56:05]

There are still some test users of DeferredImageDecoder::setEnabled:

Source/platform/graphics/BitmapImageTest.cpp:127:
Source/web/ImageDecodeBench.cpp:354:

Probably some of these should be deleted, not sure which. For now let's just
force it always on for blink so I can work on deleting the WebSetting.

[pdr., 2015-06-10 23:17:54]

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

[pdr., 2015-06-10 23:17:54]

LGTM

[chrishtr, 2015-06-11 00:07:51]

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

[chrishtr, 2015-06-11 00:07:51]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2015-06-11 00:07:52]

lgtm

[commit-bot: I haz the power, 2015-06-11 00:08:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1180663002/20001

[danakj, 2015-06-11 00:09:10]

The CQ bit was unchecked by danakj@chromium.org

[esprehn, 2015-06-11 01:09:21]

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

[esprehn, 2015-06-11 01:09:22]

lgtm

[danakj, 2015-06-11 20:09:00]

The CQ bit was checked by danakj@chromium.org

[commit-bot: I haz the power, 2015-06-11 20:09:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1180663002/20001

[commit-bot: I haz the power, 2015-06-11 20:12:47]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196969