Unregister AnimationPlayer from ActiveDOMObjects on timeline deletion.

Source/core/animation/AnimationTimeline.cpp

Index: Source/core/animation/AnimationTimeline.cpp
diff --git a/Source/core/animation/AnimationTimeline.cpp b/Source/core/animation/AnimationTimeline.cpp
index a9d7abfda6e1e39ed1396850c8a7cf600371b5d1..e490b9a0324ad01999f34d622053f8894b010561 100644
--- a/Source/core/animation/AnimationTimeline.cpp
+++ b/Source/core/animation/AnimationTimeline.cpp
@@ -77,6 +77,9 @@ AnimationTimeline::AnimationTimeline(Document* document, PassOwnPtrWillBeRawPtr<
 
 AnimationTimeline::~AnimationTimeline()
 {
+    for (const auto& player : m_players)

[sof, 2015/04/10 09:12:52]

Why are their two loops over m_players here (and dispose() first)?

Accessing other heap objects (AnimationPlayer and the hash set) is not allowed
from within dtors with Oilpan -- finalization isn't ordered.

[loyso (OOO), 2015/04/13 00:05:16]

Nice to know from now! Sorry and thanks, sof!

+        player->dispose();

[dstockwell, 2015/04/10 11:21:34]

Hmm, this should probably just move to player->timelineDestroyed() The player
should die together with it's timeline under Oilpan.

But, thinking about this patch more, we should just make setCompositorPending
early out when timeline is null.

If this is causing problems for Oilpan it's fine to just revert this patch.

+
 #if !ENABLE(OILPAN)
     for (const auto& player : m_players)
         player->timelineDestroyed();