Move global function lowestEditableAncestor() to local function in VisibleSelection.cpp

This patch moves global function |lowestEditableAncestor()| in
"EditingUtilities.{cpp,h}" to local function in "VisibleSelection.cpp" to
narrow visibility for improving code health and ease of implement composed tree
version.

This patch is a preparation of making selection to handle granularity for web
component, http://crrev.com/1277863002

BUG=513568
TEST=n/a; No behavior changes

Review URL: https://codereview.chromium.org/1318943002

git-svn-id: svn://svn.chromium.org/blink/trunk@201302 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -246,19 +246,6 @@ ContainerNode* highestEditableRoot(const PositionInComposedTree& position, Edita
     return highestEditableRoot(toPositionInDOMTree(position), editableType);
 }
 
-Element* lowestEditableAncestor(Node* node)
-{
-    while (node) {
-        if (node->hasEditableStyle())
-            return node->rootEditableElement();
-        if (isHTMLBodyElement(*node))
-            break;
-        node = node->parentNode();
-    }
-
-    return 0;
-}
-
 bool isEditablePosition(const Position& p, EditableType editableType, EUpdateStyle updateStyle)
 {
     Node* node = p.parentAnchoredEquivalent().anchorNode();

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

@@ -68,7 +68,6 @@ ContainerNode* highestEditableRoot(const PositionInComposedTree&, EditableType =
 Node* highestEnclosingNodeOfType(const Position&, bool (*nodeIsOfType)(const Node*),
     EditingBoundaryCrossingRule = CannotCrossEditingBoundary, Node* stayWithin = nullptr);
 Node* highestNodeToRemoveInPruning(Node*, Node* excludeNode = nullptr);
-Element* lowestEditableAncestor(Node*);
 
 Element* enclosingBlock(Node*, EditingBoundaryCrossingRule = CannotCrossEditingBoundary);
 Element* enclosingBlock(const Position&, EditingBoundaryCrossingRule);

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

@@ -905,6 +905,19 @@ bool VisibleSelection::isBaseFirstInComposedTree() const
     return m_baseInComposedTree.isNotNull() && m_baseInComposedTree.compareTo(m_extentInComposedTree) <= 0;
 }
 
+static Element* lowestEditableAncestor(Node* node)
+{
+    while (node) {
+        if (node->hasEditableStyle())
+            return node->rootEditableElement();
+        if (isHTMLBodyElement(*node))
+            break;
+        node = node->parentNode();
+    }
+
+    return nullptr;
+}
+
 void VisibleSelection::adjustSelectionToAvoidCrossingEditingBoundaries()
 {
     if (m_base.isNull() || m_start.isNull() || m_end.isNull())