Oilpan: promptly finalize XMLHttpRequestProgressEventThrottle.

Oilpan: promptly finalize XMLHttpRequestProgressEventThrottle.

This timer object needs to promptly stop, otherwise we run the risk
of timers firing while the object is in non-valid state waiting to be
finalized by an ongoing lazy sweep.

R=haraken
BUG=491488
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197736

[sof, 2015-06-24 11:22:35]

sigbjornf@opera.com changed reviewers:
+ oilpan-reviews@chromium.org

[sof, 2015-06-24 11:22:36]

please take a look.

[haraken, 2015-06-24 11:32:28]

LGTM

[sof, 2015-06-24 11:53:57]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-06-24 11:54:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1205843003/1

[commit-bot: I haz the power, 2015-06-24 12:02:20]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197736

[sof, 2015-06-24 15:49:04]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1211593002/ by sigbjornf@opera.com.

The reason for reverting is: This is not well-formed as-is;
XMLHttpRequestProgressEventThrottle is a part object & cannot be eagerly
finalized on its own..