Revert of Eagerly remove disposed DOMTimers as observers.

Revert of Eagerly remove disposed DOMTimers as observers. (patchset #1 id:1 of https://codereview.chromium.org/1959013002/ )

Reason for revert:
Caused issue 610606, reverting to locally investigate how/why.

Original issue's description:
> Eagerly remove disposed DOMTimers as observers.
>
> Once the coordinator lets go of a timer, no need to keep it
> around as an observer of the ExecutionContext.
>
> R=
> BUG=
>
> Committed: https://crrev.com/0a297738301705d02f57968334bd6f7c7dc95f4c
> Cr-Commit-Position: refs/heads/master@{#392309}

TBR=oilpan-reviews@chromium.org,keishi@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=

Committed: https://crrev.com/b0438b3ba5de4aa326db9197e86ed408edf710a2
Cr-Commit-Position: refs/heads/master@{#392901}

[sof, 2016-05-11 11:24:24]

Created Revert of Eagerly remove disposed DOMTimers as observers.

[commit-bot: I haz the power, 2016-05-11 11:24:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1968963002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1968963002/1

[haraken, 2016-05-11 11:31:08]

LGTM

[commit-bot: I haz the power, 2016-05-11 12:32:14]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-11 12:33:31]

Description was changed from

==========
Revert of Eagerly remove disposed DOMTimers as observers. (patchset #1 id:1 of
https://codereview.chromium.org/1959013002/ )

Reason for revert:
Caused issue 610606, reverting to locally investigate how/why.

Original issue's description:
> Eagerly remove disposed DOMTimers as observers.
> 
> Once the coordinator lets go of a timer, no need to keep it
> around as an observer of the ExecutionContext.
> 
> R=
> BUG=
> 
> Committed: https://crrev.com/0a297738301705d02f57968334bd6f7c7dc95f4c
> Cr-Commit-Position: refs/heads/master@{#392309}

TBR=oilpan-reviews@chromium.org,keishi@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=
==========

to

==========
Revert of Eagerly remove disposed DOMTimers as observers. (patchset #1 id:1 of
https://codereview.chromium.org/1959013002/ )

Reason for revert:
Caused issue 610606, reverting to locally investigate how/why.

Original issue's description:
> Eagerly remove disposed DOMTimers as observers.
>
> Once the coordinator lets go of a timer, no need to keep it
> around as an observer of the ExecutionContext.
>
> R=
> BUG=
>
> Committed: https://crrev.com/0a297738301705d02f57968334bd6f7c7dc95f4c
> Cr-Commit-Position: refs/heads/master@{#392309}

TBR=oilpan-reviews@chromium.org,keishi@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=

Committed: https://crrev.com/b0438b3ba5de4aa326db9197e86ed408edf710a2
Cr-Commit-Position: refs/heads/master@{#392901}
==========

[commit-bot: I haz the power, 2016-05-11 12:33:32]

Patchset 1 (id:??) landed as
https://crrev.com/b0438b3ba5de4aa326db9197e86ed408edf710a2
Cr-Commit-Position: refs/heads/master@{#392901}