Move character{After,Before}() for VisiblePosition to VisibleUnits.cpp

Source/core/editing/VisiblePosition.cpp

Index: Source/core/editing/VisiblePosition.cpp
diff --git a/Source/core/editing/VisiblePosition.cpp b/Source/core/editing/VisiblePosition.cpp
index 0555c26c42ce29ef1e6ee4d09795280f23552079..b805abab3ed2129c6ae0d2746083b40240b3af0e 100644
--- a/Source/core/editing/VisiblePosition.cpp
+++ b/Source/core/editing/VisiblePosition.cpp
@@ -590,31 +590,6 @@ VisiblePosition visiblePositionOf(const PositionInComposedTree& position, TextAf
     return VisiblePosition::createWithoutCanonicalization(PositionWithAffinity(toPositionInDOMTree(canonicalized.position()), canonicalized.affinity()));
 }
 
-UChar32 characterAfter(const VisiblePosition& visiblePosition)
-{
-    // We canonicalize to the first of two equivalent candidates, but the second
-    // of the two candidates is the one that will be inside the text node
-    // containing the character after this visible position.
-    Position pos = mostForwardCaretPosition(visiblePosition.deepEquivalent());
-    if (!pos.isOffsetInAnchor())
-        return 0;
-    Node* containerNode = pos.computeContainerNode();
-    if (!containerNode || !containerNode->isTextNode())
-        return 0;
-    unsigned offset = static_cast<unsigned>(pos.offsetInContainerNode());
-    Text* textNode = toText(containerNode);
-    unsigned length = textNode->length();
-    if (offset >= length)
-        return 0;
-
-    return textNode->data().characterStartingAt(offset);
-}
-
-UChar32 characterBefore(const VisiblePosition& visiblePosition)
-{
-    return characterAfter(previousPositionOf(visiblePosition));
-}
-
 IntRect absoluteCaretBoundsOf(const VisiblePosition& visiblePosition)
 {
     LayoutObject* layoutObject;