Avoid computing navigation data for nodes in the wrong navigation direction

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 868 matching lines @@
         if (element == focusedElement)
             continue;
 
         if (!element->isKeyboardFocusable() && !element->isFrameOwnerElement() && !canScrollInDirection(element, type))
             continue;
 
         FocusCandidate candidate = FocusCandidate(element, type);
         if (candidate.isNull())
             continue;
 
+        if (!isRectInDirection(type, current.rect, candidate.rect))

[fs, 2015/03/18 14:02:11]

Could you perhaps make this the first thing in distanceDataForNode instead? (To
avoid exposing isRectInDirection.) There's not a whole lot of code being run
between here and the suggested placement, so I don't think it makes a big
different "optimization-wise".

[Abhijeet Kandalkar Slow, 2015/03/18 14:26:42]

Done.

+            continue;
+
         candidate.enclosingScrollableBox = &container;
         updateFocusCandidateIfNeeded(type, current, candidate, closest);
     }
 }
 
 bool FocusController::advanceFocusDirectionallyInContainer(Node* container, const LayoutRect& startingRect, WebFocusType type)
 {
     if (!container)
         return false;
 
@@ skipping 105 matching lines @@
     return consumed;
 }
 
 DEFINE_TRACE(FocusController)
 {
     visitor->trace(m_page);
     visitor->trace(m_focusedFrame);
 }
 
 } // namespace blink