We want to move the newly-introduced RequestRestyle call from FlushAnimations
to Animation::Tick. However, nsAnimationManager::CheckAnimationRule calls
Animation::Tick so this would cause us to start posting animation restyles
within a restyle.
Typically, Animations have an effect (currently there is only one type of
effect: KeyframeEffectReadOnly) and when there is any change in timing they
pass it down to their effect. However, the Animation is dependent on the
duration of the effect for determining if it is "finished" or not. As a result,
when an effect's timing changes, the owning Animation needs to know.
(The way this *should* work is that effects should tell their animation or
trigger some chain of events that causes animation's to update themselves.
However, the current implementation of effects is fairly primitive and does
not do this or even have a reference to the owning Animation. When we
implement the script API for updating the timing properties of effects we will
have to fix this but for now it is up to code in layout/style to update the
Animation when it touches the corresponding effect's timing.)
nsAnimationManager::CheckAnimationRule currently does this by calling
Animation::Tick() which ensures the Animation's finished state is updated
accordingly.
Ultimately we want to ensure that Animation::Tick is called exactly once per
frame (and at the appropriate point in that frame) so we'd like to remove this
call from CheckAnimationRule.
This patch achieves that by:
* Making Animation::SetEffect update the animation's timing - this is necessary
for animations that are created by CheckAnimationRule and will be
necessary when once we make Animation.effect writeable from script anyway.
* Calling Animation::SetEffect even for the case when we are updating the
existing effect.
Another side-effect of calling Animation::Tick within
nsAnimationManager::CheckAnimationRule is that CSSAnimation::Tick queues
events. There are some tests (e.g. layout/style/test/test_animations.html) that
assume that animationstart events are dispatched immediately when new
animations are created. That will change with bug 1134163 but for now we
should maintain this existing behavior since changing this might introduce
compatibility issues that are best dealt with as a separate bug rather than
blocking this refactoring. To that end, this patch also explicitly queues
animationstart events for newly-created animations.
nsTransitionManager::WillRefresh and nsAnimationManager::WillRefresh are now
identical and all methods they call exist on CommonAnimationManager so we
can unify them there.
The implementations of FlushAnimations and FlushTransitions should now be all
but equivalent so this patch combines them into a single implementation on
CommonAnimationManager.
Regarding some of the minor differences between the two methods:
* The combined implementation drops the check for an empty list of collections
found only in FlushTransitions. This seems like a very minor optimization
that could possibly cause us to fail to unregister from the refresh driver
if we forgot to do so when removing the last collection.
* The combined implementation uses the loop implementation from FlushAnimations
since it is more compact.
This patch also removes the extra nested scope since it doesn't seem necessary.
There are a couple of assertions that only exist in FlushTransitions (and not
FlushAnimations). This patch moves them to RequestRestyle since they appear to
apply to either transitions or animations equally. By eliminating this
difference between FlushTransitions and FlushAnimations we should then be
in a position to combine them into a common method on the base class.
