Bug 1341648 - stylo: Include content rules from HTMLTableCellElement::WalkContentStyleRules ; r=bz

This also removes the TABLE_ATTRS_DIRTY optimization. Constructing nsMappedAttributes isn't really expensive and we do it all the time anyway.

MozReview-Commit-ID: 2krt1nFUzgl

dom/html/HTMLTableElement.h

@@ -14,8 +14,6 @@
 namespace mozilla {
 namespace dom {
 
-#define TABLE_ATTRS_DIRTY ((nsMappedAttributes*)0x1)
-
 class TableRowsCollection;
 
 class HTMLTableElement final : public nsGenericHTMLElement
@@ -232,8 +230,6 @@ protected:
 
   RefPtr<nsContentList> mTBodies;
   RefPtr<TableRowsCollection> mRows;
-  // Sentinel value of TABLE_ATTRS_DIRTY indicates that this is dirty and needs
-  // to be recalculated.
   nsMappedAttributes *mTableInheritedAttributes;
   void BuildInheritedAttributes();
   void ReleaseInheritedAttributes();