Reviewed by Darin.

        - fix http://bugs.webkit.org/show_bug.cgi?id=13572
          Arabic characters are not correctly joined when using Arial

        No tests added because standard fonts do not use the character-based shaping
        code path.

        Added shapeArabic(), a private version of u_shapeArabic() from ICU,
        patched to shape Arabic characters used in Persian, Urdu, Sindhi, etc.
        (whose contextual forms belong to the Arabic Presentation Forms-A block).

        * WebCore.xcodeproj/project.pbxproj: Added ShapeArabic.{c,h}.
        * platform/mac/FontMac.mm:
        (WebCore::shapeArabic): Changed to call shapeArabic() instead of u_shapeArabic().
        * platform/mac/ShapeArabic.c: Added. Based on ushape.c from ICU, with
        additional shaping data and logic for Arabic Presentation Forms-A. Removed
        many options that are not used in WebKit and code that malloc()ed a temporary
        buffer and reversed the string.
        (changeLamAlef):
        (specialChar):
        (getLink):
        (isTashkeelChar):
        (shapeUnicode):
        (shapeArabic):
        * platform/mac/ShapeArabic.h: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@21408 268f45cc-cd09-0410-ab3c-d52691b4dbfc