Have ElementTraversal::firstWithin() take a reference

Source/core/page/FocusController.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * 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
@@ skipping 749 matching lines @@
     if (candidate.alignment == closest.alignment) {
         if (candidate.distance < closest.distance)
             closest = candidate;
         return;
     }
 
     if (candidate.alignment > closest.alignment)
         closest = candidate;
 }
 
-void FocusController::findFocusCandidateInContainer(Node* container, const LayoutRect& startingRect, FocusDirection direction, FocusCandidate& closest)
+void FocusController::findFocusCandidateInContainer(Node& container, const LayoutRect& startingRect, FocusDirection direction, FocusCandidate& closest)
 {
-    ASSERT(container);
     Element* focusedElement = (focusedFrame() && focusedFrame()->document()) ? focusedFrame()->document()->focusedElement() : 0;
 
     Element* element = ElementTraversal::firstWithin(container);
     FocusCandidate current;
     current.rect = startingRect;
     current.focusableNode = focusedElement;
     current.visibleNode = focusedElement;
 
     for (; element; element = (element->isFrameOwnerElement() || canScrollInDirection(element, direction))
-        ? ElementTraversal::nextSkippingChildren(*element, container)
-        : ElementTraversal::next(*element, container)) {
+        ? ElementTraversal::nextSkippingChildren(*element, &container)
+        : ElementTraversal::next(*element, &container)) {
         if (element == focusedElement)
             continue;
 
         if (!element->isKeyboardFocusable() && !element->isFrameOwnerElement() && !canScrollInDirection(element, direction))
             continue;
 
         FocusCandidate candidate = FocusCandidate(element, direction);
         if (candidate.isNull())
             continue;
 
-        candidate.enclosingScrollableBox = container;
+        candidate.enclosingScrollableBox = &container;
         updateFocusCandidateIfNeeded(direction, current, candidate, closest);
     }
 }
 
 bool FocusController::advanceFocusDirectionallyInContainer(Node* container, const LayoutRect& startingRect, FocusDirection direction)
 {
     if (!container)
         return false;
 
     LayoutRect newStartingRect = startingRect;
 
     if (startingRect.isEmpty())
         newStartingRect = virtualRectForDirection(direction, nodeRectInAbsoluteCoordinates(container));
 
     // Find the closest node within current container in the direction of the navigation.
     FocusCandidate focusCandidate;
-    findFocusCandidateInContainer(container, newStartingRect, direction, focusCandidate);
+    findFocusCandidateInContainer(*container, newStartingRect, direction, focusCandidate);
 
     if (focusCandidate.isNull()) {
         // Nothing to focus, scroll if possible.
         // NOTE: If no scrolling is performed (i.e. scrollInDirection returns false), the
         // spatial navigation algorithm will skip this container.
         return scrollInDirection(container, direction);
     }
 
     if (HTMLFrameOwnerElement* frameElement = frameOwnerElement(focusCandidate)) {
         // If we have an iframe without the src attribute, it will not have a contentFrame().
@@ skipping 78 matching lines @@
         startingRect = nodeRectInAbsoluteCoordinates(container, true /* ignore border */);
         container = scrollableEnclosingBoxOrParentFrameForNodeInDirection(direction, container);
         if (container && container->isDocumentNode())
             toDocument(container)->updateLayoutIgnorePendingStylesheets();
     } while (!consumed && container);
 
     return consumed;
 }
 
 } // namespace WebCore