Specs: update the run loop and timer stuff to use the new model with task filters, priorities, and …

sky/specs/style.md

 Sky Style Language
 ==================
 
 Planed changes
 --------------
 
 Add //-to-end-of-line comments to be consistent with the script
 language.
 
 
@@ skipping 552 matching lines @@
 ```
 
 Each frame, at some defined point relative to requestAnimationFrame(),
 if a Rule has started applying, or a Rule stopped applying, to an
 element, dart:sky calls thatElement.style.clearFrameStyles() and then,
 for each Rule that now applies, calls
 thatElement.style.addFrameStyles() with the relevant StyleDeclaration
 and pseudoElement from each such Rule.
 
 
-Cascade
--------
+Update the render tree
+----------------------
 
 Simultaneously walk the tree rooted at the application Document,
 taking into account shadow trees and child distribution, and the tree
 rooted at the document's RenderNode.
 
 If you come across a node that doesn't have an assigned RenderNode,
 then create one, placing it in the appropriate place in the RenderTree
 tree, after any nodes marked isGhost=true, with ownerLayoutManager
 pointing to the parent RenderNode's layoutManager, if it has one, and,
 if it has one and autoreap is false on that layout manager, mark the
@@ skipping 477 matching lines @@
 ```
 
 The other elements don't have any default styles.
 
 These declarations are all shared between all the elements (so e.g. if
 you reach in and change the declaration that was added to a ``span``
 element, you're going to change the styles of all the other
 default-hidden elements). (In other words, in the code snippets above,
 the ``d`` variable is initialised in shared code, and only the
 addStyles() call is per-element.)