Introduce visiblePositionOf() for Position and PositionInComposedTree

Source/core/editing/VisiblePosition.h

Index: Source/core/editing/VisiblePosition.h
diff --git a/Source/core/editing/VisiblePosition.h b/Source/core/editing/VisiblePosition.h
index 02a389e7b9bcc1f3855196c51c0d176866de4674..f54d71b960ec37ba4747b8be5e0708337059df92 100644
--- a/Source/core/editing/VisiblePosition.h
+++ b/Source/core/editing/VisiblePosition.h
@@ -73,10 +73,17 @@ class CORE_EXPORT VisiblePosition final {
     DISALLOW_ALLOCATION();
 public:
     VisiblePosition() : m_affinity(VP_DEFAULT_AFFINITY) { }
+
+    // TODO(yosin) We should use |visiblePositionOf()| instead of constructor,
+    // and make constructors to have private accessibility, since constructors
+    // aren't simple, e.g. they update layout tree.
     explicit VisiblePosition(const Position&, TextAffinity = VP_DEFAULT_AFFINITY);
-    explicit VisiblePosition(const PositionInComposedTree&, TextAffinity = VP_DEFAULT_AFFINITY);
     explicit VisiblePosition(const PositionWithAffinity&);
 
+    // Node: Other than |visiblePositionOf()|, 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
@@ -105,9 +112,8 @@ public:
 #endif
 
 private:
-    template<typename Strategy>
-    void init(const PositionAlgorithm<Strategy>&, TextAffinity);
-
+    // TODO(yosin) We should use |PositionWithAffinity| to make
+    // |toPositionWithAffinity()| simpler.
     Position m_deepPosition;
     TextAffinity m_affinity;
 };
@@ -130,6 +136,7 @@ VisiblePosition rightPositionOf(const VisiblePosition&);
 
 CORE_EXPORT Position canonicalPositionOf(const Position&);
 CORE_EXPORT PositionInComposedTree canonicalPositionOf(const PositionInComposedTree&);
+
 // TODO(yosin) We should move |characterAfter()| and |characterBefore()| to
 // "VisibleUnits.cpp"
 UChar32 characterAfter(const VisiblePosition&);
@@ -148,6 +155,9 @@ VisiblePosition nextPositionOf(const VisiblePosition&, EditingBoundaryCrossingRu
 // TODO(yosin) We should move |previousPositionOf()| to "VisibleUnits.cpp"
 VisiblePosition previousPositionOf(const VisiblePosition&, EditingBoundaryCrossingRule = CanCrossEditingBoundary);
 
+CORE_EXPORT VisiblePosition visiblePositionOf(const Position&, TextAffinity = VP_DEFAULT_AFFINITY);
+CORE_EXPORT VisiblePosition visiblePositionOf(const PositionInComposedTree&, TextAffinity = VP_DEFAULT_AFFINITY);
+
 } // namespace blink
 
 #ifndef NDEBUG