Introduce previousPositionOf() for VisiblePosition

Source/core/editing/VisiblePosition.h

 /*
  * Copyright (C) 2004, 2008 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 78 matching lines @@
     bool isNotNull() const { return m_deepPosition.isNotNull(); }
     bool isOrphan() const { return m_deepPosition.isOrphan(); }
 
     Position deepEquivalent() const { return m_deepPosition; }
     Position toParentAnchoredPosition() const { return deepEquivalent().parentAnchoredEquivalent(); }
     PositionWithAffinity toPositionWithAffinity() const { return PositionWithAffinity(m_deepPosition, m_affinity); }
     TextAffinity affinity() const { return m_affinity; }
 
     // next() and previous() will increment/decrement by a character cluster.
     VisiblePosition next(EditingBoundaryCrossingRule = CanCrossEditingBoundary) const;
-    VisiblePosition previous(EditingBoundaryCrossingRule = CanCrossEditingBoundary) const;
     VisiblePosition honorEditingBoundaryAtOrBefore(const VisiblePosition&) const;
     VisiblePosition honorEditingBoundaryAtOrAfter(const VisiblePosition&) const;
     VisiblePosition skipToStartOfEditingBoundary(const VisiblePosition&) const;
     VisiblePosition skipToEndOfEditingBoundary(const VisiblePosition&) const;
 
     VisiblePosition left() const;
     VisiblePosition right() const;
 
     UChar32 characterAfter() const;
-    UChar32 characterBefore() const { return previous().characterAfter(); }
+    UChar32 characterBefore() const;
 
     // FIXME: This does not handle [table, 0] correctly.
     Element* rootEditableElement() const { return m_deepPosition.isNotNull() ? m_deepPosition.anchorNode()->rootEditableElement() : 0; }
 
     // Rect is local to the returned layoutObject
     LayoutRect localCaretRect(LayoutObject*&) const;
     // Bounds of (possibly transformed) caret in absolute coords
     IntRect absoluteCaretBounds() const;
     // Abs x/y position of the caret ignoring transforms.
     // FIXME: navigation with transforms should be smarter.
@@ skipping 18 matching lines @@
     TextAffinity m_affinity;
 };
 
 EphemeralRange makeRange(const VisiblePosition&, const VisiblePosition&);
 
 CORE_EXPORT Position canonicalPositionOf(const Position&);
 CORE_EXPORT PositionInComposedTree canonicalPositionOf(const PositionInComposedTree&);
 PositionWithAffinity honorEditingBoundaryAtOrBeforeOf(const PositionWithAffinity&, const Position& anchor);
 PositionInComposedTreeWithAffinity honorEditingBoundaryAtOrBeforeOf(const PositionInComposedTreeWithAffinity&, const PositionInComposedTree& anchor);
 
+// TODO(yosin) We should move |previousPositionOf()| to "VisibleUnits.cpp"
+VisiblePosition previousPositionOf(const VisiblePosition&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
+
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const blink::VisiblePosition*);
 void showTree(const blink::VisiblePosition&);
 #endif
 
 #endif // VisiblePosition_h