Do not (re)start NavigatorGamepad updating once detached.

Do not (re)start NavigatorGamepad updating once detached.

Following r187750, NavigatorGamepad uses DOMWindowProperty::frame()
to access its window and document, dispatching and handling events
via those when activated and receiving platform event updates.

With Oilpan enabled, a DOMWindowProperty instance will be informed
of frame & document detachment via willDetachGlobalObjectFromFrame(),
with the frame remaining alive until the next GC sweep. Without
Oilpan, frame destruction is synchronous.

Consequently, a NavigatorGamepad with a now-detached frame() should
not reactivate itself, as the weak frame() reference will become
null once the next GC has struck. NavigatorGamepad relies on
frame() being non-null when activated.

Insist on the frame being non-detached to (re)activate. The
difference in behavior from the previous check is only observable
with Oilpan enabled, hence no need to make it suitably conditional.

R=haraken
BUG=340522
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=187811

[sof, 2015-01-01 07:56:41]

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

[sof, 2015-01-01 07:56:41]

Please take a look.

Bots reporting some flaky gamepad crashes,


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

Locally reproducible, but GC timing sensitive.

[haraken, 2015-01-01 09:49:43]

LGTM, thanks for the investigation and fix.

[sof, 2015-01-01 09:52:03]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-01-01 09:53:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/828983002/20001

[commit-bot: I haz the power, 2015-01-01 09:55:51]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=187811