When updating animations, we shouldn't unnecessarily clobber the "wins in
cascade" state of their properties since this can lead to unnecessary restyles
when we then decide we need to update the cascade.
RestyleManager currently has a piece of state for tracking if throttled
animations are up-to-date or not. Actually, it's not so much about throttled
animations but really about outstanding changes to animation styles (which
is typically expected to be due to throttling animations but there are
other cases that invalidate the animation style rule that we should be
considering here).
We now have that same information stored in the EffectCompositor so we can
remove the redundant state from RestyleManager. Furthermore, the state stored
in EffectCompositor is more accurate since it captures the case when animation
style needs to be updated twice within a tick, or when nothing needs to be
updated within a tick.
This patch, therefore, introduces EffectCompositor::HasPendingStyleUpdates in
place of setting RestyleManager::mLastUpdateForThrottledAnimations.
nsTransitionManager also uses mLastUpdateForThrottledAnimations to warn if we
have not processed throttled animations. We can't use HasPendingStyleUpdates
here however, since it will return true in the case where we have triggered new
transitions in the process of restyling. However, any new transitions will
trigger "standard" (i.e. not throttled) restyles so we introduce another
method, HasThrottledStyleUpdates, that returns true only if we have outstanding
throttled updates and use this for the warning inside nsTransitionManager.
nsPresContext contains a mLastStyleUpdateForAllAnimations flag which is simply
used to prevent unnecessarily posting restyles when throttled animations are
already up to date. Since part 13 we now accurately record whether we have
posted a restyle for each throttled animation and only post a restyle if we
have not done so already. As a result, this flag is no longer needed since
calling PostRestyleForThrottledAnimations is effectively a noop when throttled
animations are up-to-date.
This flag is no longer needed because in bug 1232563 we introduced a more
thorough optimization that detects when the animation is not changing by
comparing the progress value between samples and avoids requesting restyles
when it does not change.
Now that we track whether or not animations are up to date using the hashset in
EffectCompositor, we can remove the mStyleRuleRefreshTime flag that is, as of
part 5 of this patch series, now only used for detecting whether or not
animations are up to date.
In order to preserve the existing behavior of FlushAnimations, however, this
patch temporarily introduces a method to indicate if there are throttled
animations or not.
It might not be obvious that FlushAnimations is only concerned with throttled
animations due to its name. FlushAnimations is simply intended to post
animation restyles for out-of-date animations. Any animations that are *not*
throttled will either be up to date, or we will have already posted an
animation restyle so we only need to consider throttled animations in this case.
This patch continues to migrate functionality from
AnimationCollection::RequestRestyle to EffectCompositor::RequestRestyle.
In order to post the animation restyle from the EffectCompositor, this patch
also moves the PostRestyleForAnimation method to EffectCompositor.
The GetElementToRestyle method is temporarily duplicated in both
EffectCompositor and AnimationCollection however we will remove the version in
AnimationCollection later in this patch series.
In this patch series we are gradually migrating style rule updating
functionality from AnimationCollection to EffectCompositor. This patch moves
part of the RequestRestyle method from one class to the other.
Note that in both cases we only call SetNeedsStyleFlush if we haven't already
posted an animation restyle. (In the case of AnimationCollection we check this
using the mHasPendingAnimationRestyle flag, and in EffectCompositor case we
simply check if the element is already in the "needs restyle" hashmap. If it is,
either we already have a throttled restyle and have called SetNeedsStyleFlush or
we have a standard restyle and have posted an animation restyle.)
The added check for a null pres context matches the behavior of
AnimationCollection::RequestRestyle which has an equivalent early return at the
beginning of the function.
This patch uses the presence/absence of (pseudo-)elements in the "needs
animation rule update" hashmap on EffectCompositor to detect if a style update
is required. The various flags in AnimationCollection that do a similar job
still remain so that we can remove them one-by-one in subsequent patches in
this series.
This is in preparation for moving RequestRestyle to EffectCompositor (and
because we'll run into compile issues if we don't since AnimationCommon.h
includes too many interdependent definitions).
Since we want to track elements needing a restyle on EffectCompositor we need
to scope it to an nsPresContext rather than just making if a collection of
static methods.
Even though the content of the root scroll frame is the root element, the primary frame of the root element is never the root scroll frame. This is even true if the normal primary frame of the root element is not created (say because it is display: none). Leaving the primary frame of the root element to be null even though there are frames (the root scroll frame, and the canvas frame) that have the root element as their content.
This behaviour is more consistent by not ignoring a root scroll frame when it exists.
And to several functions above it in the callgraph, ones that no longer need an
nsRenderingContext.
--HG--
extra : rebase_source : 331d00be421316a7071ab4b93894431c36a031d5
Jonathan Kew
Brian Birtles
Nicholas Nethercote
Matt Woodrow
Markus Stange
Jim Mathies
Kartikaya Gupta
Bogdan Postelnicu
Timothy Nikkel
Daniel Holbert
Christoph Kerschbaumer
Randall Barker
Wes Kocher
Mats Palmgren
Joel Maher
Thinker K.F. Li
Cameron McCormack