2008-03-19  Justin Garcia  <justin.garcia@apple.com>

        Reviewed by Oliver.

        <rdar://problem/5794920> Acid3: Assertion failure in VisiblePosition::previous when clicking on results (17004)
        
        The position inside an empty inline-block was a candidate, but upstream and downstream
        would move across it without stopping.  This confused canonicalPosition, since no more
        than two candidates should have the same upstream/downstream (be visually equivalent).
        
        Code was added intentionally in isCandidate to make VisiblePositions inside empty 
        inline-blocks, so we need to make upstream/downstream understand that.

        * dom/Position.cpp:
        (WebCore::endsOfNodeAreVisuallyDistinctPositions): upstream and downstream used to only
        stop when entering or leaving a non-inline element (referred to as a "block").  We must also 
        avoid entering or leaving an empty inline-block.  This will allow a VisiblePosition there, to 
        match up with what the code in isCandidate intended.
        (WebCore::enclosingVisualBoundary): Removed enclosingBlock and replaced it with this.
        (WebCore::Position::upstream): Added better comments, called the new functions.
        (WebCore::Position::downstream): Ditto.
        * dom/Position.h:

LayoutTests:

2008-03-19  Justin Garcia  <justin.garcia@apple.com>

        Reviewed by Oliver.
        
        <rdar://problem/5794920> Acid3: Assertion failure in VisiblePosition::previous when clicking on results (17004)

        * editing/pasteboard/4989774.html: Updated to wait for the images to load before trying to copy it.
        * editing/selection/5794920-1-expected.txt: Added.
        * editing/selection/5794920-1.html: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@31161 268f45cc-cd09-0410-ab3c-d52691b4dbfc