Removal all idle-task implementations in toBlob

Removal all idle-task implementations in toBlob

BUG=564218
Committed: https://crrev.com/72fc4074be5f53812829e6272f5e246319f444bd
Cr-Commit-Position: refs/heads/master@{#370908}

[xlai (Olivia), 2016-01-21 20:41:05]

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

[xlai (Olivia), 2016-01-21 20:41:06]

I've cleaned up the code a bit, before shipping toBlob.

[Justin Novosad, 2016-01-21 21:03:55]

All that sweat and tears. Sniff :'(

lgtm

[xlai (Olivia), 2016-01-22 03:22:51]

The CQ bit was checked by xlai@chromium.org

[xlai (Olivia), 2016-01-22 03:22:51]

The patchset sent to the CQ was uploaded after l-g-t-m from junov@chromium.org
Link to the patchset: https://codereview.chromium.org/1614173002/#ps20001
(title: "Rebased with master")

[commit-bot: I haz the power, 2016-01-22 03:24:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1614173002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1614173002/20001

[commit-bot: I haz the power, 2016-01-22 04:57:32]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-01-22 04:59:26]

Description was changed from

==========
Removal all idle-task implementations in toBlob

BUG=564218
==========

to

==========
Removal all idle-task implementations in toBlob

BUG=564218

Committed: https://crrev.com/72fc4074be5f53812829e6272f5e246319f444bd
Cr-Commit-Position: refs/heads/master@{#370908}
==========

[commit-bot: I haz the power, 2016-01-22 04:59:27]

Patchset 2 (id:??) landed as
https://crrev.com/72fc4074be5f53812829e6272f5e246319f444bd
Cr-Commit-Position: refs/heads/master@{#370908}

[xlai (Olivia), 2016-01-26 23:07:30]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1637163002/ by xlai@chromium.org.

The reason for reverting is: I want to pull back the implementations for
idle-tasks, because I find that it is possible that this implementation is the
one we should adopt in canvas.toBlob instead of the other implementation..