Reviewed by Hyatt

    Reviewed by Hyatt

        Some improvements for paste, including some new code to annotate
        whitespace when writing to the pasteboard to ensure that the meaning
        of the markup on the pasteboard is unambiguous.

        There is also new code for reading this annotated markup from the pasteboard,
        removing the nodes that were added only to prevent ambiguity.

        * WebCore.pbproj/project.pbxproj: Added html_interchange.h and html_interchange.cpp files.
        The header should have been added earlier, but I did not do so.
        * khtml/editing/html_interchange.cpp: Added.
        (convertHTMLTextToInterchangeFormat):
        * khtml/editing/html_interchange.h: Added some new constants for use with whitespace annotations.
        * khtml/editing/htmlediting.cpp:
        (khtml::ReplacementFragment::ReplacementFragment): Now looks for and removes annotations added for whitespace.
        Also fixed a bug in the code that counts blocks in a fragment.
        (khtml::ReplacementFragment::isInterchangeConvertedSpaceSpan): New helper. Recognizes annotation spans.
        (khtml::ReplacementFragment::insertNodeBefore): New helper.
        (khtml::ReplaceSelectionCommand::doApply): Fixed a bug in the code that sets the start position
        for the replacement after deleting. This was causing a bug when pasting at the end of a block.
        * khtml/editing/htmlediting.h: Add some new declarations.
        * khtml/xml/dom2_rangeimpl.cpp:
        (DOM::RangeImpl::toHTML): Calls to startMarkup now pass true for the new annotate flag.
        * khtml/xml/dom_nodeimpl.cpp:
        (NodeImpl::stringValueForRange): New helper.
        (NodeImpl::renderedText): New helper to return only the rendered text in a node.
        (NodeImpl::startMarkup): Now takes an additional flag to control whether interchange annotations
        should be added. Called by the paste code.
        * khtml/xml/dom_nodeimpl.h: Added and modified function declarations.

        New test to check the khtml::ReplaceSelectionCommand::doApply fix.
        * layout-tests/editing/pasteboard/paste-text-010-expected.txt: Added.
        * layout-tests/editing/pasteboard/paste-text-010.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8096 268f45cc-cd09-0410-ab3c-d52691b4dbfc