Reviewed by Jian Li.

        [Chromium] Filter out URLs with a file scheme from text/uri-list when dragging.
        https://bugs.webkit.org/show_bug.cgi?id=38227

        Unfortunately, the simple fix of not populating the drag data with file URLs doesn't work
        since the default drop handling uses the drag data URL to navigate to dropped files/URLs.
        For now, we hack around the problem in the Chromium platform, but the proper long term
        solution is to change DragController::performDrag to check dragData::asFilenames().

        No new tests.

        * platform/chromium/ClipboardChromium.cpp:
        (WebCore::ClipboardChromium::getData):
        (WebCore::ClipboardChromium::types):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@58378 268f45cc-cd09-0410-ab3c-d52691b4dbfc