Use RenderStyle::isCollapsibleWhiteSpace when renderer is available.

Source/core/dom/Position.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 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 1045 matching lines @@
     if (isNull())
         return Position();
 
     if (isHTMLBRElement(*upstream().deprecatedNode()))
         return Position();
 
     Position prev = previousCharacterPosition(affinity);
     if (prev != *this && prev.deprecatedNode()->inSameContainingBlockFlowElement(deprecatedNode()) && prev.deprecatedNode()->isTextNode()) {
         String string = toText(prev.deprecatedNode())->data();
         UChar c = string[prev.deprecatedEditingOffset()];
-        if (considerNonCollapsibleWhitespace ? (isSpaceOrNewline(c) || c == noBreakSpace) : isCollapsibleWhitespace(c))
+        if (considerNonCollapsibleWhitespace ? (isSpaceOrNewline(c) || c == noBreakSpace) : prev.deprecatedNode()->renderer()->style()->isCollapsibleWhiteSpace(c))

[esprehn, 2014/04/01 00:25:55]

How do you know the renderer() is available here?

             if (isEditablePosition(prev))
                 return prev;
     }
 
     return Position();
 }
 
 // This assumes that it starts in editable content.
 Position Position::trailingWhitespacePosition(EAffinity, bool considerNonCollapsibleWhitespace) const
 {
     ASSERT(isEditablePosition(*this, ContentIsEditable, DoNotUpdateStyle));
     if (isNull())
         return Position();
 
     VisiblePosition v(*this);
     UChar c = v.characterAfter();
     // The space must not be in another paragraph and it must be editable.
     if (!isEndOfParagraph(v) && v.next(CannotCrossEditingBoundary).isNotNull())
-        if (considerNonCollapsibleWhitespace ? (isSpaceOrNewline(c) || c == noBreakSpace) : isCollapsibleWhitespace(c))
+        if (considerNonCollapsibleWhitespace ? (isSpaceOrNewline(c) || c == noBreakSpace) : deprecatedNode()->renderer()->style()->isCollapsibleWhiteSpace(c))

[esprehn, 2014/04/01 00:25:55]

ditto

             return *this;
 
     return Position();
 }
 
 void Position::getInlineBoxAndOffset(EAffinity affinity, InlineBox*& inlineBox, int& caretOffset) const
 {
     getInlineBoxAndOffset(affinity, primaryDirection(), inlineBox, caretOffset);
 }
 
@@ skipping 292 matching lines @@
     pos.showTreeForThis();
 }
 
 void showTree(const WebCore::Position* pos)
 {
     if (pos)
         pos->showTreeForThis();
 }
 
 #endif