Background color applied on a selection of text is lost when the selection is deleted

Source/core/editing/DeleteSelectionCommand.cpp

 /*
  * Copyright (C) 2005 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 274 matching lines @@
     // typing style at the start of the selection, nor is there a reason to 
     // compute the style at the start of the selection after deletion (see the 
     // early return in calculateTypingStyleAfterDelete).
     if (m_upstreamStart.deprecatedNode() == m_downstreamEnd.deprecatedNode() && m_upstreamStart.deprecatedNode()->isTextNode())
         return;
 
     if (shouldNotInheritStyleFrom(*m_selectionToDelete.start().anchorNode()))
         return;
 
     // Figure out the typing style in effect before the delete is done.
-    m_typingStyle = EditingStyle::create(m_selectionToDelete.start());
+    m_typingStyle = EditingStyle::create(m_selectionToDelete.start(), EditingStyle::EditingPropertiesInEffect);

[yosin_UTC9, 2013/09/09 04:57:48]

How about changing default value of EditingStyle::create() to
EditingPropertiesInEffect? 

It seems following functions also need to pass EditingPropertiesInEffect:
- CompositeEditCommand::moveParagraphs(),
- ReplaceSelectionCommand::removeRedundantStylesAndKeepStyleSpanInline
- ReplaceSelectionCommand::handleStyleSpansBeforeInsertion
- ReplaceSelectionCommand::handleStyleSpans
- InsertParagraphSeparatorCommand::calculateStyleBeforeInsertion

If all of them using EditingPropertiesInEffect, 
do we need to have OnlyEditingInheritableProperties?

     m_typingStyle->removeStyleAddedByNode(enclosingAnchorElement(m_selectionToDelete.start()));
 
     // If we're deleting into a Mail blockquote, save the style at end() instead of start()
     // We'll use this later in computeTypingStyleAfterDelete if we end up outside of a Mail blockquote
     if (enclosingNodeOfType(m_selectionToDelete.start(), isMailBlockquote))
         m_deleteIntoBlockquoteStyle = EditingStyle::create(m_selectionToDelete.end());

[yosin_UTC9, 2013/09/09 04:57:48]

Should we pass EditingStyle::EditingPropertiesInEffect?

     else
         m_deleteIntoBlockquoteStyle = 0;
 }
 
 bool DeleteSelectionCommand::handleSpecialCaseBRDelete()
 {
     Node* nodeAfterUpstreamStart = m_upstreamStart.computeNodeAfterPosition();
     Node* nodeAfterDownstreamStart = m_downstreamStart.computeNodeAfterPosition();
     // Upstream end will appear before BR due to canonicalization
     Node* nodeAfterUpstreamEnd = m_upstreamEnd.computeNodeAfterPosition();
@@ skipping 528 matching lines @@
 
 // Normally deletion doesn't preserve the typing style that was present before it.  For example,
 // type a character, Bold, then delete the character and start typing.  The Bold typing style shouldn't
 // stick around.  Deletion should preserve a typing style that *it* sets, however.
 bool DeleteSelectionCommand::preservesTypingStyle() const
 {
     return m_typingStyle;
 }
 
 } // namespace WebCore