Bug 1418076 part 3. Get rid of nsIDOMHTMLDocument's head attribute. r=mystor

MozReview-Commit-ID: Cj7l9TqmAby

dom/html/nsHTMLDocument.cpp

@@ -1067,16 +1067,6 @@ nsHTMLDocument::SetDomain(const nsAString& aDomain, ErrorResult& rv)
   rv = NodePrincipal()->SetDomain(newURI);
 }
 
-NS_IMETHODIMP
-nsHTMLDocument::GetHead(nsISupports** aHead)
-{
-  *aHead = nullptr;
-
-  Element* head = GetHeadElement();
-
-  return head ? CallQueryInterface(head, aHead) : NS_OK;
-}
-
 nsIHTMLCollection*
 nsHTMLDocument::Images()
 {

dom/interfaces/html/nsIDOMHTMLDocument.idl

@@ -16,8 +16,6 @@ interface nsISelection;
 [uuid(cd31e61f-cfc2-4b91-9385-17b6a2d0633d)]
 interface nsIDOMHTMLDocument : nsIDOMDocument
 {
-  readonly attribute nsISupports          head;
-
   // If aContentType is not something supported by nsHTMLDocument and
   // the HTML content sink, trying to write to the document will
   // probably throw.