Reviewed by Richard Williamson.

    Reviewed by Richard Williamson.

        - fixed <rdar://problem/4184366> WebPDFView should conform to the WebDocumentSelection protocol

        * Misc.subproj/WebNSAttributedStringExtras.h: Added.
        * Misc.subproj/WebNSAttributedStringExtras.m: Added.
        (-[NSAttributedString _web_attributedStringByStrippingAttachmentCharacters]):
        New category on NSAttributedString, initially contains this one method that had been in WebHTMLView.

        * WebView.subproj/WebHTMLView.m:
        (-[WebHTMLView _writeSelectionWithPasteboardTypes:toPasteboard:cachedAttributedString:]):
        now uses _web_attributedStringByStrippingAttachmentCharacters

        * WebView.subproj/WebPDFView.h:
        now conforms to WebDocumentSelection protocol
        * WebView.subproj/WebPDFView.m:
        (-[WebPDFView selectionRect]):
        new, implementation of WebDocumentSelection protocol method
        (-[WebPDFView pasteboardTypesForSelection]):
        ditto
        (-[WebPDFView writeSelectionWithPasteboardTypes:toPasteboard:]):
        ditto

        * WebKit.pbproj/project.pbxproj:
        updated for new files

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@9823 268f45cc-cd09-0410-ab3c-d52691b4dbfc