Move a member function parentEditingBoundary() out from PositionAlgorithm<Strategy> template class

This patch moves a member function |parentEditingBoundary()| in
|PositionAlgorithm<Strategy>| template class for a preparation of making it
as static function in "VisibileUnits.cpp" since it is used only in
"VisibileUnits.cpp".

BUG=518738
TEST=n/a; no behavior changes

Review URL: https://codereview.chromium.org/1298233004

git-svn-id: svn://svn.chromium.org/blink/trunk@200827 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/editing/Position.cpp

@@ -470,22 +470,32 @@ static ContainerNode* nonShadowBoundaryParentNode(Node* node)
 }
 
 template <typename Strategy>
-Node* PositionAlgorithm<Strategy>::parentEditingBoundary() const
+static Node* parentEditingBoundaryAlgorithm(const PositionAlgorithm<Strategy>& position)
 {
-    if (!m_anchorNode)
-        return 0;
+    Node* const anchorNode = position.anchorNode();
+    if (!anchorNode)
+        return nullptr;
 
-    Node* documentElement = m_anchorNode->document().documentElement();
+    Node* documentElement = anchorNode->document().documentElement();
     if (!documentElement)
-        return 0;
+        return nullptr;
 
-    Node* boundary = computeContainerNode();
-    while (boundary != documentElement && nonShadowBoundaryParentNode<Strategy>(boundary) && m_anchorNode->hasEditableStyle() == Strategy::parent(*boundary)->hasEditableStyle())
+    Node* boundary = position.computeContainerNode();
+    while (boundary != documentElement && nonShadowBoundaryParentNode<Strategy>(boundary) && anchorNode->hasEditableStyle() == Strategy::parent(*boundary)->hasEditableStyle())
         boundary = nonShadowBoundaryParentNode<Strategy>(boundary);
 
     return boundary;
 }
 
+Node* parentEditingBoundary(const Position& position)
+{
+    return parentEditingBoundaryAlgorithm<EditingStrategy>(position);
+}
+
+Node* parentEditingBoundary(const PositionInComposedTree& position)
+{
+    return parentEditingBoundaryAlgorithm<EditingInComposedTreeStrategy>(position);
+}
 
 template <typename Strategy>
 bool PositionAlgorithm<Strategy>::atStartOfTree() const

third_party/WebKit/Source/core/editing/Position.h

@@ -182,8 +182,6 @@ public:
     bool atFirstEditingPositionForNode() const;
     bool atLastEditingPositionForNode() const;
 
-    Node* parentEditingBoundary() const;
-
     bool atStartOfTree() const;
     bool atEndOfTree() const;
 
@@ -252,6 +250,11 @@ using PositionInComposedTree = PositionAlgorithm<EditingInComposedTreeStrategy>;
 // since it is used only in "editing/commands/"
 CORE_EXPORT bool isRenderedCharacter(const Position&);
 
+// TODO(yosin) We should make |parentEditingBoundary()| as static function
+// in "VisibleUnits.cpp", since it is used only there.
+CORE_EXPORT Node* parentEditingBoundary(const Position&);
+CORE_EXPORT Node* parentEditingBoundary(const PositionInComposedTree&);
+
 template <typename Strategy>
 bool operator==(const PositionAlgorithm<Strategy>& a, const PositionAlgorithm<Strategy>& b)
 {

third_party/WebKit/Source/core/editing/VisibleUnits.cpp

@@ -460,7 +460,7 @@ typedef unsigned (*BoundarySearchFunction)(const UChar*, unsigned length, unsign
 static VisiblePosition previousBoundary(const VisiblePosition& c, BoundarySearchFunction searchFunction)
 {
     Position pos = c.deepEquivalent();
-    Node* boundary = pos.parentEditingBoundary();
+    Node* boundary = parentEditingBoundary(pos);
     if (!boundary)
         return VisiblePosition();
 
@@ -538,7 +538,7 @@ static VisiblePosition previousBoundary(const VisiblePosition& c, BoundarySearch
 static VisiblePosition nextBoundary(const VisiblePosition& c, BoundarySearchFunction searchFunction)
 {
     Position pos = c.deepEquivalent();
-    Node* boundary = pos.parentEditingBoundary();
+    Node* boundary = parentEditingBoundary(pos);
     if (!boundary)
         return VisiblePosition();