Notification.requestPermission callback should be optional
https://bugs.webkit.org/show_bug.cgi?id=108196

Reviewed by Adam Barth.

Source/WebCore:

Spec says it should be optional.
http://notifications.spec.whatwg.org/#notification

Test: fast/notifications/notifications-request-permission-optional.html

* GNUmakefile.list.am:
* Modules/notifications/Notification.h:
(Notification):
* Modules/notifications/Notification.idl:
* Target.pri:
* UseJSC.cmake:
* UseV8.cmake:
* WebCore.gypi:
* WebCore.vcproj/WebCore.vcproj:
* WebCore.vcxproj/WebCore.vcxproj:
* WebCore.vcxproj/WebCore.vcxproj.filters:
* WebCore.xcodeproj/project.pbxproj:
* bindings/js/JSNotificationCustom.cpp: Removed.
* bindings/scripts/CodeGeneratorJS.pm:
(GenerateParametersCheck):
* bindings/v8/custom/V8NotificationCustom.cpp: Removed.

LayoutTests:

Specs says it should be optional.
http://notifications.spec.whatwg.org/#notification

* fast/notifications/notifications-request-permission-optional-expected.txt: Added.
* fast/notifications/notifications-request-permission-optional.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144126 268f45cc-cd09-0410-ab3c-d52691b4dbfc