Move computeInlineBoxPosition() out from VisiblePosition

Source/core/editing/VisibleUnits.cpp

Index: Source/core/editing/VisibleUnits.cpp
diff --git a/Source/core/editing/VisibleUnits.cpp b/Source/core/editing/VisibleUnits.cpp
index d5e17b3e63757b12f57908028939f9275ccc4a05..27a981b81484c3402d960b5cf76e8d5f3bb19d14 100644
--- a/Source/core/editing/VisibleUnits.cpp
+++ b/Source/core/editing/VisibleUnits.cpp
@@ -973,7 +973,7 @@ VisiblePosition previousLinePosition(const VisiblePosition &visiblePosition, Lay
         return VisiblePosition();
 
     RootInlineBox* root = 0;
-    InlineBox* box = visiblePosition.computeInlineBoxPosition().inlineBox;
+    InlineBox* box = computeInlineBoxPosition(visiblePosition).inlineBox;
     if (box) {
         root = box->root().prevRootBox();
         // We want to skip zero height boxes.
@@ -1026,7 +1026,7 @@ VisiblePosition nextLinePosition(const VisiblePosition &visiblePosition, LayoutU
         return VisiblePosition();
 
     RootInlineBox* root = 0;
-    InlineBox* box = visiblePosition.computeInlineBoxPosition().inlineBox;
+    InlineBox* box = computeInlineBoxPosition(visiblePosition).inlineBox;
     if (box) {
         root = box->root().nextRootBox();
         // We want to skip zero height boxes.