Add Traversal<*Element>::firstAncestor() API

Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1702 matching lines @@
     FrameView* view = m_frame->view();
     RenderView* renderView = m_frame->contentRenderer();
 
     if (!view || !renderView)
         return FloatRect();
 
     LayoutRect selectionRect = renderView->selectionBounds(clipToVisibleContent);
     return clipToVisibleContent ? intersection(selectionRect, view->visibleContentRect()) : selectionRect;
 }
 
+static inline HTMLFormElement* associatedFormElement(HTMLElement& element)
+{
+    if (isHTMLFormElement(element))
+        return &toHTMLFormElement(element);
+    return element.formOwner();
+}
+
 // Scans logically forward from "start", including any child frames.
 static HTMLFormElement* scanForForm(Node* start)
 {
     if (!start)
         return 0;
+
     HTMLElement* element = start->isHTMLElement() ? toHTMLElement(start) : Traversal<HTMLElement>::next(*start);
     for (; element; element = Traversal<HTMLElement>::next(*element)) {
-        if (isHTMLFormElement(*element))
-            return toHTMLFormElement(element);
-
-        if (HTMLFormElement* owner = element->formOwner())
-                return owner;
+        if (HTMLFormElement* form = associatedFormElement(*element))
+            return form;
 
         if (isHTMLFrameElementBase(*element)) {
             Node* childDocument = toHTMLFrameElementBase(*element).contentDocument();
             if (HTMLFormElement* frameResult = scanForForm(childDocument))
                 return frameResult;
         }
     }
     return 0;
 }
 
 // We look for either the form containing the current focus, or for one immediately after it
 HTMLFormElement* FrameSelection::currentForm() const
 {
     // Start looking either at the active (first responder) node, or where the selection is.
     Node* start = m_frame->document()->focusedElement();
     if (!start)
         start = this->start().deprecatedNode();
+    if (!start)
+        return 0;
 
     // Try walking up the node tree to find a form element.
-    Node* node;
-    for (node = start; node; node = node->parentNode()) {
-        if (isHTMLFormElement(*node))
-            return toHTMLFormElement(node);
-        if (node->isHTMLElement()) {
-            HTMLFormElement* owner = toHTMLElement(node)->formOwner();
-            if (owner)
-                return owner;
-        }
+    for (HTMLElement* element = Traversal<HTMLElement>::firstAncestorOrSelf(*start); element; element = Traversal<HTMLElement>::firstAncestor(*element)) {
+        if (HTMLFormElement* form = associatedFormElement(*element))
+            return form;
     }
 
     // Try walking forward in the node tree to find a form element.
     return scanForForm(start);
 }
 
 void FrameSelection::revealSelection(const ScrollAlignment& alignment, RevealExtentOption revealExtentOption)
 {
     LayoutRect rect;
 
@@ skipping 102 matching lines @@
     sel.showTreeForThis();
 }
 
 void showTree(const WebCore::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
 }
 
 #endif