- fix http://bugs.webkit.org/show_bug.cgi?id=10735
          Clicking in SVG results causes WebKit to consume 100% CPU for several minutes

        No test since there is no change in functionality.

        * CMakeLists.txt:
        * WebCore.pro:
        * WebCore.xcodeproj/project.pbxproj: Added PositionIterator.{cpp,h}.
        * WebCoreSources.bkl:
        * dom/Position.cpp:
        (WebCore::Position::Position): Added converting constructor from
        PositionIterator.
        (WebCore::Position::previous): Changed assert() to ASSERT().
        (WebCore::Position::next): Ditto.
        (WebCore::isStreamer): Changed the argument to a PositionIterator.
        (WebCore::Position::upstream): Changed to use PositionIterator.
        (WebCore::Position::downstream): Ditto.
        (WebCore::Position::inRenderedText): Made public.
        (WebCore::Position::hasRenderedNonAnonymousDescendantsWithHeight): Changed
        into a static member function.
        (WebCore::Position::nodeIsUserSelectNone): Ditto.
        * dom/Position.h:
        * dom/PositionIterator.cpp: Added. A Position iterator with constant-time
        increment, decrement, and several predicates on the Position it is at.
        Conversion to/from Position is O(n) in the offset.
        (WebCore::PositionIterator::increment):
        (WebCore::PositionIterator::decrement):
        (WebCore::PositionIterator::atStart):
        (WebCore::PositionIterator::atEnd):
        (WebCore::PositionIterator::atStartOfNode):
        (WebCore::PositionIterator::atEndOfNode):
        (WebCore::PositionIterator::isCandidate):
        * dom/PositionIterator.h: Added.
        (WebCore::PositionIterator::PositionIterator):
        (WebCore::PositionIterator::node):
        (WebCore::PositionIterator::offsetInLeafNode):
        * editing/htmlediting.cpp:
        (WebCore::nextCandidate): Changed to use PositionIterator.
        (WebCore::previousCandidate): Changed to use PositionIterator.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@19734 268f45cc-cd09-0410-ab3c-d52691b4dbfc