Ensure cancellation of animation timer in a detached state.

Ensure cancellation of animation timer in a detached state.

If an SVG element becomes detached from its document, its animations will
be paused. Make sure this really cancels any "once" timers that might
be scheduled.

R=haraken,fs@opera.com
BUG=3690
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188139

[sof, 2015-01-09 06:31:45]

sigbjornf@opera.com changed reviewers:
+ dmazzoni@chromium.org, ed@opera.com, fs@opera.com, je_julie.kim@samsung.com,
oilpan-reviews@chromium.org, pdr@chromium.org

[sof, 2015-01-09 06:31:45]

Please take a look.

Following r187775, we've been running into some flaky crashers on the Oilpan
bots,


https://storage.googleapis.com/chromium-layout-test-archives/WebKit_Win_Oilpa...

These, I believe, show up a more general problem of what happens once SVG
animation timers are active in documents that become detached. The slowness of
Oilpan debug build and documents with detached frames can have a longer lifetime
with Oilpan, simply triggers the problem more reliably.

It can be reproduced non-Oilpan by running e.g.,

 foo$ blink/tools/run_layout_tests.sh <...> --repeat=2 --debug
svg/animations/svg-animation-policy-once.html

[haraken, 2015-01-09 07:06:32]

LGTM, but I want to have fs@ take another look.

[fs, 2015-01-09 09:34:58]

lgtm

[sof, 2015-01-09 09:36:10]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-01-09 09:36:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/811763005/20001

[commit-bot: I haz the power, 2015-01-09 10:37:16]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=188139