Reviewed by Tor Arne Vestbø.

        [Qt] Reintroduce QWebElementCollection

        Revert the patch that has replaced QWebElementCollection
        with QList<QWebElement>. Update the tests accordingly.

        Remove the constness of the return type of QWebElement operator[].

        https://bugs.webkit.org/show_bug.cgi?id=30767

        * Api/qwebelement.cpp:
        (QWebElement::findAll):
        (QWebElementCollectionPrivate::QWebElementCollectionPrivate):
        (QWebElementCollectionPrivate::create):
        (QWebElementCollection::QWebElementCollection):
        (QWebElementCollection::operator=):
        (QWebElementCollection::~QWebElementCollection):
        (QWebElementCollection::operator+):
        (QWebElementCollection::append):
        (QWebElementCollection::count):
        (QWebElementCollection::at):
        (QWebElementCollection::toList):
        * Api/qwebelement.h:
        (const_iterator::begin):
        (const_iterator::end):
        (const_iterator::operator[]):
        * Api/qwebframe.cpp:
        (QWebFrame::findAllElements):
        * Api/qwebframe.h:
        * QtLauncher/main.cpp:
        (MainWindow::selectElements):
        * tests/qwebelement/tst_qwebelement.cpp:
        (tst_QWebElement::simpleCollection):
        (tst_QWebElement::iteration):
        (tst_QWebElement::emptyCollection):
        (tst_QWebElement::appendCollection):
        (tst_QWebElement::nullSelect):
        (tst_QWebElement::hasSetFocus):
        (tst_QWebElement::render):
        * tests/qwebpage/tst_qwebpage.cpp:
        (tst_QWebPage::inputMethods):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@50058 268f45cc-cd09-0410-ab3c-d52691b4dbfc