Reviewed by Geoffrey Garen.

        Refactor WriteBarrier and DeprecatedPtr to have less code duplication.
        https://bugs.webkit.org/show_bug.cgi?id=54608

        Make use of the tricks used for Handle, et al to avoid duplicating all
        of the logic for DeprecatedPtr and WriteBarrier simply to support known
        vs. unknown types.

        * JavaScriptCore.xcodeproj/project.pbxproj:
        * collector/handles/Global.h:
        (JSC::Global::internalSet):
        * collector/handles/Handle.h:
        (JSC::Handle::Handle):
        (JSC::Handle::get):
        * runtime/JSArray.cpp:
        (JSC::JSArray::sortNumeric):
        * runtime/JSObject.h:
        (JSC::JSObject::inlineGetOwnPropertySlot):
        * runtime/SlotAccessor.h: Added.
        (JSC::SlotTypes::getFromBaseType):
        (JSC::SlotTypes::convertToBaseType):
        (JSC::SlotTypes::getFromSlot):
        (JSC::SlotTypes::toJSValue):
        (JSC::SlotTypes::validateUpcast):
        (JSC::SlotAccessor::operator->):
        (JSC::SlotAccessor::operator*):
        * runtime/WeakGCPtr.h:
        (JSC::WeakGCPtr::get):
        (JSC::WeakGCPtr::internalSet):
        * runtime/WriteBarrier.h:
        (JSC::DeprecatedPtr::DeprecatedPtr):
        (JSC::DeprecatedPtr::get):
        (JSC::DeprecatedPtr::slot):
        (JSC::DeprecatedPtr::operator=):
        (JSC::WriteBarrierTranslator::convertToStorage):
        (JSC::WriteBarrierTranslator::convertFromStorage):
        (JSC::WriteBarrierBase::set):
        (JSC::WriteBarrierBase::get):
        (JSC::WriteBarrierBase::clear):
        (JSC::WriteBarrierBase::slot):
        (JSC::WriteBarrierBase::operator UnspecifiedBoolType*):
        (JSC::WriteBarrierBase::operator!):
        (JSC::WriteBarrierBase::setWithoutWriteBarrier):
        (JSC::WriteBarrier::WriteBarrier):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@78856 268f45cc-cd09-0410-ab3c-d52691b4dbfc