Get rid of redundant member function PositionAlgorithm<Strategy>::{upstream,downstream}

Source/core/editing/Position.h

Index: Source/core/editing/Position.h
diff --git a/Source/core/editing/Position.h b/Source/core/editing/Position.h
index 1a7b840b9ef3ad31c3d302adb6b0584c29d796b3..9294f3d16c515dc858586d4093af3d2bb1e661c0 100644
--- a/Source/core/editing/Position.h
+++ b/Source/core/editing/Position.h
@@ -160,11 +160,6 @@ public:
     bool atStartOfTree() const;
     bool atEndOfTree() const;
 
-    // These return useful visually equivalent positions.
-    // FIXME: We should use mostForwardCaretPosition and mostBackwardPosition.
-    PositionAlgorithm<Strategy> upstream(EditingBoundaryCrossingRule = CannotCrossEditingBoundary) const;
-    PositionAlgorithm<Strategy> downstream(EditingBoundaryCrossingRule = CannotCrossEditingBoundary) const;
-
     static PositionAlgorithm<Strategy> beforeNode(Node* anchorNode);
     static PositionAlgorithm<Strategy> afterNode(Node* anchorNode);
     static PositionAlgorithm<Strategy> inParentBeforeNode(const Node& anchorNode);