Fix the "inactive document" condition for HTMLMediaElement GC

Fix the "inactive document" condition for HTMLMediaElement GC

document().isActive() is the wrong condition, and triggered an assert:
https://codereview.chromium.org/584633004

The assert was added in https://codereview.chromium.org/552303006

The original assumption was that !document().isActive() implies that
ActiveDOMObject::stop() has been called, but since a document is
inactive also in the beginning of its lifecycle, that is not true.

Instead use the internal m_active state to determine if stop(), which
calls m_asyncEventQueue->close(), has been called.

TEST=LayoutTests/media/gc-pending-event-inactive-document.html

This test hits the assert if the condition is !document().isActive().

BUG=400659

[philipj_slow, 2014-09-19 12:35:24]

philipj@opera.com changed reviewers:
+ fs@opera.com

[philipj_slow, 2014-09-19 12:35:25]

PTAL

[fs, 2014-09-19 12:40:50]

https://codereview.chromium.org/585903002/diff/1/Source/core/html/HTMLMediaEl...
File Source/core/html/HTMLMediaElement.cpp (right):

https://codereview.chromium.org/585903002/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:3533: if (!m_active) {
Isn't the element also inactive after being removed from the document?

[philipj_slow, 2014-09-19 12:48:47]

https://codereview.chromium.org/585903002/diff/1/Source/core/html/HTMLMediaEl...
File Source/core/html/HTMLMediaElement.cpp (right):

https://codereview.chromium.org/585903002/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:3533: if (!m_active) {
On 2014/09/19 12:40:50, fs wrote:
> Isn't the element also inactive after being removed from the document?

Yes, both the comment and the code (m_active) is talking about the element now.

[philipj_slow, 2014-09-19 12:52:34]

Bah, still failing on
http/tests/misc/delete-frame-during-readystatechange-with-gc-after-video-removal.html:
http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/2...

[philipj_slow, 2014-09-19 12:56:33]

https://codereview.chromium.org/585903002/diff/1/Source/core/html/HTMLMediaEl...
File Source/core/html/HTMLMediaElement.cpp (right):

https://codereview.chromium.org/585903002/diff/1/Source/core/html/HTMLMediaEl...
Source/core/html/HTMLMediaElement.cpp:3533: if (!m_active) {
On 2014/09/19 12:48:47, philipj wrote:
> On 2014/09/19 12:40:50, fs wrote:
> > Isn't the element also inactive after being removed from the document?
> 
> Yes, both the comment and the code (m_active) is talking about the element
now.

Oh, you meant the bit in HTMLMediaElement::removedFrom. Sigh. Yes. So much fail.

[philipj_slow, 2014-09-19 13:53:59]

Abandoned in favor of https://codereview.chromium.org/587683002/