Use RenderStyle::isCollapsibleWhiteSpace when renderer is available.

Source/core/editing/TextIterator.h

Index: Source/core/editing/TextIterator.h
diff --git a/Source/core/editing/TextIterator.h b/Source/core/editing/TextIterator.h
index 6ab68639759017bc428dbcd411ef3a5f878a8215..1046c95b0363c7c5319e40435f8e138441bc1626 100644
--- a/Source/core/editing/TextIterator.h
+++ b/Source/core/editing/TextIterator.h
@@ -48,19 +48,6 @@ enum TextIteratorBehavior {
 };
 typedef unsigned TextIteratorBehaviorFlags;
 
-// FIXME: Can't really answer this question correctly without knowing the white-space mode.
-// FIXME: Move this somewhere else in the editing directory. It doesn't belong here.
-inline bool isCollapsibleWhitespace(UChar c)
-{
-    switch (c) {
-        case ' ':
-        case '\n':
-            return true;
-        default:
-            return false;
-    }
-}
-
 String plainText(const Range*, TextIteratorBehaviorFlags = TextIteratorDefaultBehavior);
 PassRefPtr<Range> findPlainText(const Range*, const String&, FindOptions);
 PassRefPtr<Range> findPlainText(const Position& start, const Position& end, const String&, FindOptions);