This adds a generic walker method that cna be used to retrieve AnimationPlayerActor's
target DOM nodes in a way that they can be highlighted/selected later in the inspector.
Making the AnimationPlayerActor return the nodeActor directly wouldn't fully work, as
the walker would have missed the missing parent nodeFronts updates.
On the UI, this adds a new component in each PlayerWidget that displays a preview of the
target DOM nodes, highlight them on hover, and select them on click.
(Re-land after backout)
The animation-controler was in charge of getting new animation players and refreshing
the UI when done. This is still the case, but it now listens for mutation events from
the actor too, and when they happen, it simply asks the ui to refresh again.
Also, animations with playState "finished" that remain in the animation inspector panel
can now be played again.
This adds a playbackRate <select> dropdown next to the list of other playback
control buttons (play/pause, rw, fwd).
The list shows presets, unless the current rate isn't part of these presets
in which case it also shows this rate in the list.
The widget was created as a reusable component with a simple API, like the
PlayerMetaDataHeader.
Backed out changeset 527c548ff03c (bug 1149711)
Backed out changeset 2fe22ffef154 (bug 1120833)
Backed out changeset 501fa7c170ed (bug 1120833)
CLOSED TREE
The animation-controler was in charge of getting new animation players and refreshing
the UI when done. This is still the case, but it now listens for mutation events from
the actor too, and when they happen, it simply asks the ui to refresh again.
Also, animations with playState "finished" that remain in the animation inspector panel
can now be played again.
This makes the AnimationsActor listen for animation mutations after each
call to getAnimationPlayersForNode on the code that was passed in.
Whenever animations are added or removed, an event is sent to the front
with the list of changes.
The server doesn't know when the client doesn't require updates for the
current node anymore, so it exposes a new method for this.
Note that removed events for finished aniations are skipped, because the
corresponding animations can still be seeked/resumed, so we want the
AnimationPlayerActor to be preserved.
