Use PositionWithAffinity as internal representation of VisiblePostion

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 52 matching lines @@
 //    abc^def where "^" represent |Position|
 // When above text line wrapped after "abc"
 //    abc|  UPSTREAM |VisiblePosition|
 //    |def  DOWNSTREAM |VisiblePosition|
 //
 // NOTE: UPSTREAM affinity will be used only if pos is at end of a wrapped line,
 // otherwise it will be converted to DOWNSTREAM.
 class CORE_EXPORT VisiblePosition final {
     DISALLOW_ALLOCATION();
 public:
-    VisiblePosition() : m_affinity(VP_DEFAULT_AFFINITY) { }
+    VisiblePosition();
 
     // Node: Other than |createVisiblePosition()|, we should not use
     // |createWithoutCanonicalization()|.
     static VisiblePosition createWithoutCanonicalization(const PositionWithAffinity& canonicalized);
 
     // Intentionally delete |operator==()| and |operator!=()| for reducing
     // compilation error message.
     // TODO(yosin) We'll have |equals()| when we have use cases of checking
     // equality of both position and affinity.
     bool operator==(const VisiblePosition&) const = delete;
     bool operator!=(const VisiblePosition&) const = delete;
 
-    bool isNull() const { return m_deepPosition.isNull(); }
-    bool isNotNull() const { return m_deepPosition.isNotNull(); }
-    bool isOrphan() const { return m_deepPosition.isOrphan(); }
+    bool isNull() const { return m_positionWithAffinity.isNull(); }
+    bool isNotNull() const { return m_positionWithAffinity.isNotNull(); }
+    bool isOrphan() const { return deepEquivalent().isOrphan(); }
 
-    Position deepEquivalent() const { return m_deepPosition; }
+    Position deepEquivalent() const { return m_positionWithAffinity.position(); }
     Position toParentAnchoredPosition() const { return deepEquivalent().parentAnchoredEquivalent(); }
-    PositionWithAffinity toPositionWithAffinity() const { return PositionWithAffinity(m_deepPosition, m_affinity); }
-    TextAffinity affinity() const { return m_affinity; }
+    PositionWithAffinity toPositionWithAffinity() const { return m_positionWithAffinity; }
+    TextAffinity affinity() const { return m_positionWithAffinity.affinity(); }
 
     DECLARE_TRACE();
 
 #ifndef NDEBUG
     void debugPosition(const char* msg = "") const;
     void formatForDebugger(char* buffer, unsigned length) const;
     void showTreeForThis() const;
 #endif
 
 private:
-    explicit VisiblePosition(const Position&, TextAffinity);
+    explicit VisiblePosition(const PositionWithAffinity&);
 
-    // TODO(yosin) We should use |PositionWithAffinity| to make
-    // |toPositionWithAffinity()| simpler.
-    Position m_deepPosition;
-    TextAffinity m_affinity;
+    PositionWithAffinity m_positionWithAffinity;
 };
 
 // TODO(yosin) We should move |honorEditingBoundaryAtOr{Before,After} to
 // "VisibleUnits.cpp" as static function.
 // next() and previous() will increment/decrement by a character cluster.
 VisiblePosition honorEditingBoundaryAtOrBefore(const VisiblePosition&, const Position& anchor);
 PositionWithAffinity honorEditingBoundaryAtOrBeforeOf(const PositionWithAffinity&, const Position& anchor);
 PositionInComposedTreeWithAffinity honorEditingBoundaryAtOrBeforeOf(const PositionInComposedTreeWithAffinity&, const PositionInComposedTree& anchor);
 VisiblePosition honorEditingBoundaryAtOrAfter(const VisiblePosition&, const Position& anchor);
 
 CORE_EXPORT VisiblePosition createVisiblePosition(const Position&, TextAffinity = VP_DEFAULT_AFFINITY);
 CORE_EXPORT VisiblePosition createVisiblePosition(const PositionWithAffinity&);
 CORE_EXPORT VisiblePosition createVisiblePosition(const PositionInComposedTree&, TextAffinity = VP_DEFAULT_AFFINITY);
 
 } // 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