Limit visibility {Left,Right}BoundaryOfLine() to SelectionModifier only

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

 /*
  * Copyright (C) 2004 Apple Computer, 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 230 matching lines @@
 CORE_EXPORT VisiblePositionInFlatTree
 LogicalStartOfLine(const VisiblePositionInFlatTree&);
 // TODO(yosin) Return values of |VisiblePosition| version of
 // |logicalEndOfLine()| with shadow tree isn't defined well. We should not use
 // it for shadow tree.
 CORE_EXPORT VisiblePosition LogicalEndOfLine(const VisiblePosition&);
 CORE_EXPORT VisiblePositionInFlatTree
 LogicalEndOfLine(const VisiblePositionInFlatTree&);
 CORE_EXPORT bool IsLogicalEndOfLine(const VisiblePosition&);
 CORE_EXPORT bool IsLogicalEndOfLine(const VisiblePositionInFlatTree&);
-VisiblePosition LeftBoundaryOfLine(const VisiblePosition&, TextDirection);
-VisiblePosition RightBoundaryOfLine(const VisiblePosition&, TextDirection);
 
 // paragraphs (perhaps a misnomer, can be divided by line break elements)
 // TODO(yosin) Since return value of |startOfParagraph()| with |VisiblePosition|
 // isn't defined well on flat tree, we should not use it for a position in
 // flat tree.
 CORE_EXPORT VisiblePosition
 StartOfParagraph(const VisiblePosition&,
                  EditingBoundaryCrossingRule = kCannotCrossEditingBoundary);
 CORE_EXPORT VisiblePositionInFlatTree
 StartOfParagraph(const VisiblePositionInFlatTree&,
@@ skipping 95 matching lines @@
                                             const VisiblePosition&,
                                             EditableType);
 
 Position PreviousRootInlineBoxCandidatePosition(Node*,
                                                 const VisiblePosition&,
                                                 EditableType);
 
 }  // namespace blink
 
 #endif  // VisibleUnits_h