Speed up moving cursor/selection up or down past non-renderered elements.

Source/core/editing/VisibleUnits.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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 61 matching lines @@
     }
     return 0;
 }
 
 // FIXME: consolidate with code in previousLinePosition.
 static Position previousRootInlineBoxCandidatePosition(Node* node, const VisiblePosition& visiblePosition, EditableType editableType)
 {
     Node* highestRoot = highestEditableRoot(visiblePosition.deepEquivalent(), editableType);
     Node* previousNode = previousLeafWithSameEditability(node, editableType);
 
-    while (previousNode && inSameLine(firstPositionInOrBeforeNode(previousNode), visiblePosition))
+    while (previousNode && (!previousNode->renderer() || inSameLine(firstPositionInOrBeforeNode(previousNode), visiblePosition)))
         previousNode = previousLeafWithSameEditability(previousNode, editableType);
 
     while (previousNode && !previousNode->isShadowRoot()) {
         if (highestEditableRoot(firstPositionInOrBeforeNode(previousNode), editableType) != highestRoot)
             break;
 
         Position pos = previousNode->hasTagName(brTag) ? positionBeforeNode(previousNode) :
             createLegacyEditingPosition(previousNode, caretMaxOffset(previousNode));
 
         if (pos.isCandidate())
             return pos;
 
         previousNode = previousLeafWithSameEditability(previousNode, editableType);
     }
     return Position();
 }
 
 static Position nextRootInlineBoxCandidatePosition(Node* node, const VisiblePosition& visiblePosition, EditableType editableType)
 {
     Node* highestRoot = highestEditableRoot(visiblePosition.deepEquivalent(), editableType);
     Node* nextNode = nextLeafWithSameEditability(node, editableType);
-    while (nextNode && inSameLine(firstPositionInOrBeforeNode(nextNode), visiblePosition))
+    while (nextNode && (!nextNode->renderer() || inSameLine(firstPositionInOrBeforeNode(nextNode), visiblePosition)))
         nextNode = nextLeafWithSameEditability(nextNode, ContentIsEditable);
 
     while (nextNode && !nextNode->isShadowRoot()) {
         if (highestEditableRoot(firstPositionInOrBeforeNode(nextNode), editableType) != highestRoot)
             break;
 
         Position pos;
         pos = createLegacyEditingPosition(nextNode, caretMinOffset(nextNode));
 
         if (pos.isCandidate())
@@ skipping 1297 matching lines @@
 {
     return direction == LTR ? logicalStartOfLine(c) : logicalEndOfLine(c);
 }
 
 VisiblePosition rightBoundaryOfLine(const VisiblePosition& c, TextDirection direction)
 {
     return direction == LTR ? logicalEndOfLine(c) : logicalStartOfLine(c);
 }
 
 }