Specs: Move the LayoutManager and RenderNode logic from Element to

sky/specs/dom.md

Index: sky/specs/dom.md
diff --git a/sky/specs/dom.md b/sky/specs/dom.md
index 6cfe67fb122b9cedaf0386968a94f1a557695199..6dc8230a90b3f8a4620ec57bf750f3b053d99bca 100644
--- a/sky/specs/dom.md
+++ b/sky/specs/dom.md
@@ -30,6 +30,21 @@ abstract class Node : EventTarget { // implemented in C++
   virtual void parentChangeCallback(ParentNode? oldParent, ParentNode? newParent, ChildNode? previousSibling, ChildNode? nextSibling); // O(N) in descendants (calls attached/detached)
   virtual void attachedCallback(); // noop
   virtual void detachedCallback(); // noop
+
+  readonly attribute ElementStyleDeclarationList? style; // O(1)
+    // for nodes that aren't reachable from the Application Document, returns null
+    // (so in particular orphaned subtrees and nodes in module documents don't have one)
+    //  -- should be updated when the node's parent chain changes (same time as, e.g.,
+    //     the id hashtable is updated)
+    // also always returns null for ContentElement elements and ShadowRoot nodes
+  readonly attribute RenderNode? renderNode; // O(1)
+    // this will be null until the first time it is rendered
+    // it becomes null again when it is taken out of the rendering (see style.md)
+  abstract virtual LayoutManagerConstructor getLayoutManager(); // O(1)
+  void resetLayoutManager(); // O(1)
+    // if renderNode is non-null:
+    //   sets renderNode.layoutManager to null
+    //   sets renderNode.needsManager to true
 }
 
 abstract class ParentNode : Node {
@@ -69,18 +84,11 @@ abstract class Element : ParentNode {
   virtual void attributeChangeCallback(String name, String? oldValue, String? newValue); // noop
   // TODO(ianh): does a node ever need to know when it's been redistributed?
 
-  readonly attribute ElementStyleDeclarationList style; // O(1)
-  readonly attribute RenderNode? renderNode; // O(1)
-    // this will be null until the first time it is rendered
   virtual LayoutManagerConstructor getLayoutManager(); // O(1)
     // default implementation looks up the 'display' property and returns the value:
     //   if (renderNode)
     //     return renderNode.getProperty(phDisplay);
     //   return null;
-  void resetLayoutManager(); // O(1)
-    // if renderNode is non-null:
-    //   sets renderNode.layoutManager to null
-    //   sets renderNode.needsManager to true
 }
 
 class Text : Node {
@@ -90,6 +98,9 @@ class Text : Node {
   void replaceWith(String node); // O(1) // special case override of Node.replaceWith()
 
   virtual void valueChangeCallback(String? oldValue, String? newValue); // noop
+
+  virtual LayoutManagerConstructor getLayoutManager(); // O(1)
+    // default implementation returns TextLayoutManager's constructor
 }
 
 class DocumentFragment : ParentNode {
@@ -110,20 +121,14 @@ class ShadowRoot : TreeScope {
 
 class Document : TreeScope {
   constructor (ChildArguments... nodes); // O(N) in number of arguments plus all their descendants
-}
 
-class SelectorQuery {
-  constructor (String selector); // O(F()) where F() is the complexity of the selector
-
-  Boolean matches(Element element); // O(F())
-  Element? find(Element root); // O(N*F())+O(M) where N is the number of descendants and M the average depth of the tree
-  Element? find(DocumentFragment root); // O(N*F())+O(M) where N is the number of descendants and M the average depth of the tree
-  Element? find(TreeScope root); // O(N*F()) where N is the number of descendants
-  Array<Element> findAll(Element root); // O(N*F())+O(N*M) where N is the number of descendants and M the average depth of the tree
-  Array<Element> findAll(DocumentFragment root); // O(N*F())+O(N*M) where N is the number of descendants and M the average depth of the tree
-  Array<Element> findAll(TreeScope root); // O(N*F()) where N is the number of descendants
+  virtual LayoutManagerConstructor getLayoutManager(); // O(1)
+    // default implementation returns sky.rootLayoutManager;
 }
 
+attribute LayoutManagerConstructor rootLayoutManager; // O(1)
+  // initially configured to return BlockLayoutManager
+
 
 // BUILT-IN ELEMENTS
 
@@ -254,4 +259,16 @@ interface ElementConstructor {
   constructor attribute String tagName;
   constructor attribute Boolean shadow;
 }
+
+class SelectorQuery {
+  constructor (String selector); // O(F()) where F() is the complexity of the selector
+
+  Boolean matches(Element element); // O(F())
+  Element? find(Element root); // O(N*F())+O(M) where N is the number of descendants and M the average depth of the tree
+  Element? find(DocumentFragment root); // O(N*F())+O(M) where N is the number of descendants and M the average depth of the tree
+  Element? find(TreeScope root); // O(N*F()) where N is the number of descendants
+  Array<Element> findAll(Element root); // O(N*F())+O(N*M) where N is the number of descendants and M the average depth of the tree
+  Array<Element> findAll(DocumentFragment root); // O(N*F())+O(N*M) where N is the number of descendants and M the average depth of the tree
+  Array<Element> findAll(TreeScope root); // O(N*F()) where N is the number of descendants
+}
 ```