Reviewed by John Sullivan.

    Reviewed by John Sullivan.

        - fix <rdar://problem/5491054> REGRESSION (Mail, plain-text only): Nothing happens
          when you click on rdar://<num>&<num> links (or AOL links in Safari)

        Remove the non-useful concept of a "malformed"/"invalid" URL.

        There are URLs we can parse, and others we can't, but that's not sufficient to
        determine if we should try to work with the URL. It's entirely possible that
        a so-called "malformed" URL will work just fine if it's passed to the right
        software.

        * platform/KURL.h: Removed isMalformed() and isValid().

        * loader/Cache.cpp: (WebCore::Cache::requestResource): Removed unneeded check
        if the URL is valid. But do check for an empty URL just to guarantee we don't
        trip up with a null string. It's possible we can remove this empty URL check
        later, but it's less risky to leave the empty string behavior alone for now.

        * loader/FrameLoader.cpp:
        (WebCore::FrameLoader::urlSelected): Removed unneeded check if the URL is valid.
        Back on 2007-07-08, we realized that we needed to allow empty URLs. But we also
        need to allow other URLs here. This is the code path from the Mail case.
        (WebCore::FrameLoader::submitForm): Replaced URL validity check with a check
        for an empty URL (same reasoning as for requestResource above).

        * page/InspectorController.cpp: (WebCore::InspectorResource::type):
        * rendering/RenderObject.cpp: (WebCore::RenderObject::addPDFURLRect):
        Removed unneeded check for an invalid URL. In both of these cases it's definitely
        safe to allow event an empty URL.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@25769 268f45cc-cd09-0410-ab3c-d52691b4dbfc