Reviewed by Antti.

        - fix <rdar://problem/4889753> REGRESSION: Selection doesn't continue with drag selecting
          when autoscrolling vertically (in Notes as well as Safari)

        The bug doesn't happen inside DumpRenderTree, so I was unable to make an automated
        regression test.

        * manual-tests/autoscroll-when-outside-window.html: Added.

        * rendering/RenderLayer.cpp: (WebCore::RenderLayer::autoscroll): Removed unneeded null
        check for the layer's renderer and the document, neither of which can be null. Call
        the new updateSelectionForMouseDrag instead of doing selection updating here.

        * page/EventHandler.h:
        * page/EventHandler.cpp:
        (WebCore::EventHandler::handleMouseDraggedEvent): Refactored most of the logic
        about updating the selection into updateSelectionForMouseDrag.
        (WebCore::EventHandler::updateSelectionForMouseDrag): Added. The public version of
        this function takes no parameters, and is for use from auto-scrolling code. The
        private version of this function takes node and point parameters and contains the
        shared code, including everything from updateSelectionForMouseDragOverPosition.
        Aside from the code motion, variable name changes, and sharing more code, this
        differs from the old code in RenderLayer::autoscroll in the following ways:

          1) The old code did hit testing only in the layer that was auto-scrolling,
             and the new code instead starts the hit testing at the root layer, which is
             better because it's the same thing we do for mouse moved events. Further,
             the code to do this by calling convertToLayerCoords had a bug  because the
             x and y variables were uninitialized.
          2) The old code passed false for active to HitTestRequest, which was wrong.
             The new code passes true. This flag needs to be true for hit testing done
             while the mouse is down and false for hit testing done while the mouse is up.
          3) The old code did not have the SVG-specific logic to match the mouse moved case.
          4) The old code wouldn't do any selection updating if the return value from hitTest
             was false, which is incorrect. The new code ignores the return value as it should.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@24957 268f45cc-cd09-0410-ab3c-d52691b4dbfc
5 files changed