Introduce lineDirectionPointForBlockDirectionNavigationOf() for VisiblePosition

Source/core/editing/VisiblePosition.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Portions Copyright (c) 2011 Motorola Mobility, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 679 matching lines @@
 IntRect VisiblePosition::absoluteCaretBounds() const
 {
     LayoutObject* layoutObject;
     LayoutRect localRect = localCaretRect(layoutObject);
     if (localRect.isEmpty() || !layoutObject)
         return IntRect();
 
     return layoutObject->localToAbsoluteQuad(FloatRect(localRect)).enclosingBoundingBox();
 }
 
-int VisiblePosition::lineDirectionPointForBlockDirectionNavigation() const
+// TODO(yosin) We should move a global function
+// |lineDirectionPointForBlockDirectionNavigationOf()| to "FrameSelection.h"
+// as static function.
+int lineDirectionPointForBlockDirectionNavigationOf(const VisiblePosition& visiblePosition)
 {
-    if (isNull())
+    if (visiblePosition.isNull())
         return 0;
 
     LayoutObject* layoutObject;
-    LayoutRect localRect = localCaretRect(layoutObject);
+    LayoutRect localRect = visiblePosition.localCaretRect(layoutObject);
     if (localRect.isEmpty() || !layoutObject)
         return 0;
 
     // This ignores transforms on purpose, for now. Vertical navigation is done
     // without consulting transforms, so that 'up' in transformed text is 'up'
     // relative to the text, not absolute 'up'.
     FloatPoint caretPoint = layoutObject->localToAbsolute(FloatPoint(localRect.location()));
     LayoutObject* containingBlock = layoutObject->containingBlock();
     if (!containingBlock)
         containingBlock = layoutObject; // Just use ourselves to determine the writing mode if we have no containing block.
@@ skipping 52 matching lines @@
     else
         fprintf(stderr, "Cannot showTree for (nil) VisiblePosition.\n");
 }
 
 void showTree(const blink::VisiblePosition& vpos)
 {
     vpos.showTreeForThis();
 }
 
 #endif