Disable newline selection highlighting for vertical and RTL text.

Source/core/layout/line/InlineTextBox.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 171 matching lines @@
         }
     }
 
     return state;
 }
 
 bool InlineTextBox::hasWrappedSelectionNewline() const
 {
     SelectionState state = selectionState();
     return RuntimeEnabledFeatures::selectionPaintingWithoutSelectionGapsEnabled()
+        // TODO(wkorman): Remove horizontal restriction once vertical text is operational.
+        && isHorizontal()

[chrishtr, 2015/09/18 21:34:28]

Only for left-to-right writing mode. RTL is also broken.

[wkorman, 2015/09/18 22:15:11]

Done.

         && (root().lastSelectedBox() == this)
         && (state == SelectionStart || state == SelectionInside);
 }
 
 float InlineTextBox::newlineSpaceWidth() const
 {
     const ComputedStyle& styleToUse = lineLayoutItem().styleRef(isFirstLineStyle());
     return styleToUse.font().spaceWidth();
 }
 
@@ skipping 401 matching lines @@
     printedCharacters = fprintf(stderr, "\t%s %p", obj.name(), obj.debugPointer());
     const int layoutObjectCharacterOffset = 75;
     for (; printedCharacters < layoutObjectCharacterOffset; printedCharacters++)
         fputc(' ', stderr);
     fprintf(stderr, "(%d,%d) \"%s\"\n", start(), start() + len(), value.utf8().data());
 }
 
 #endif
 
 } // namespace blink