Make content animatable
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cleanup embedder/compositor/constellation/script messages
Fix: #17226#17200#17201
This is work in progress. Some tests still fail.
I'd like to get early feedback as it's a pretty large PR.
There is nothing fundamentally new. Basically, I added TopLevelBrowsingContrextId to the relevant messages between the embedder, the compositor and the constellation, and enforced the PipelineId to be attached to each ScriptMsg (see #17201).
I unaliased all the ScriptMsg. It was getting difficult to understand the nature of the message as ScriptMsg was used aliased CompositorMsg sometimes (CompositorMsg is an actually type of message already). I renamed constellation_chan to script_to_constellation_chan, again, for clarification.
This cleanup code is necessary for #15934 and for tabs support.
/cc @asajeffrey can I ask you to look at this? No need for a formal review, I need feedback at this stage.
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Don't convert zero component value to 'auto' in clone__moz_image_region.
Currently Gecko treats 'auto' component value as zero for animation.
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https://bugzilla.mozilla.org/show_bug.cgi?id=1387951
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For CSS Transitions we want this case to return Err() so we know that the two
values are not interpolable.
For CSS Animations/Web Animations we implement discrete animation as the
fallback behavior when Err() is returned.
column-count should be greater than or equal to 1. Also it should be less than
or equal to nsStyleColumn_kMaxColumnCount since we limit it in
set_column_count().
Make scroll-snap-{coordinate, destination} discrete animation.
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https://bugzilla.mozilla.org/show_bug.cgi?id=1387941
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Make -moz-appearance animatable
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We convert a perspective function into a ComputedMatrix, but we apply the
perspective length to a wrong matrix item. We should put it into m34,
instead of m43. m43 is for translate parameter Z.
Introduce and derive ComputeSquaredDistance
This new trait merges the former `Animatable` methods `compute_distance` and `compute_squared_distance`.
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