Reviewed by John

    Reviewed by John

        Fix for this bug:

        <rdar://problem/3926142> REGRESSION (Mail): Deleting text decreases quote level

        * khtml/editing/htmlediting.cpp:
        (khtml::DeleteSelectionCommand::initializePositionData): Change test that will prevent block
        merging. End-of-line test was just wrong. Call new start-of and end-of paragraph functions
        added to visible_position files.
        (khtml::DeleteSelectionCommand::moveNodesAfterNode): Add tests for BR elements, which makes
        tests to determine when to stop moving nodes more complete and correct. Also improved comments.
        * khtml/editing/visible_position.cpp:
        (khtml::isFirstVisiblePositionInParagraph): New function.
        (khtml::isLastVisiblePositionInParagraph): New function.
        * khtml/editing/visible_position.h: Update header accordingly.
        * layout-tests/editing/deleting/delete-block-merge-contents-002-expected.txt: New results, slightly different from former
        results but still correct.
        * layout-tests/editing/deleting/delete-block-merge-contents-007-expected.txt: Ditto.
        * layout-tests/editing/deleting/delete-block-merge-contents-018-expected.txt: Added.
        * layout-tests/editing/deleting/delete-block-merge-contents-018.html: Added.
        * layout-tests/editing/deleting/delete-block-merge-contents-019-expected.txt: Added.
        * layout-tests/editing/deleting/delete-block-merge-contents-019.html: Added.
        * layout-tests/editing/deleting/delete-block-merge-contents-020-expected.txt: Added.
        * layout-tests/editing/deleting/delete-block-merge-contents-020.html: Added.
        * layout-tests/editing/deleting/delete-block-merge-contents-021-expected.txt: Added.
        * layout-tests/editing/deleting/delete-block-merge-contents-021.html: Added.
        * layout-tests/editing/deleting/delete-line-014-expected.txt: These new results are actually better, and fix a bug.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8341 268f45cc-cd09-0410-ab3c-d52691b4dbfc