Support both MutationObserver and WebKitMutationObserver
https://bugs.webkit.org/show_bug.cgi?id=109776

Reviewed by Ojan Vafai.

Source/WebCore:

We should allow new MutationObserver now that we support parser generated
mutations. This leaves the old prefixed constructor in until we decide
people don't depend on it.

Test: fast/dom/MutationObserver/mutation-observer-prefix.html

* page/DOMWindow.idl:

LayoutTests:

* fast/dom/MutationObserver/added-out-of-order.html:
* fast/dom/MutationObserver/callback-arguments.html:
* fast/dom/MutationObserver/clear-transient-without-delivery.html:
* fast/dom/MutationObserver/create-during-delivery.html:
* fast/dom/MutationObserver/cross-document.html:
* fast/dom/MutationObserver/database-callback-delivery.html:
* fast/dom/MutationObserver/delivery-order.html:
* fast/dom/MutationObserver/disconnect-cancel-pending.html:
* fast/dom/MutationObserver/document-fragment-insertion.html:
* fast/dom/MutationObserver/end-of-task-delivery.html:
* fast/dom/MutationObserver/filesystem-callback-delivery.html:
* fast/dom/MutationObserver/inline-event-listener.html:
* fast/dom/MutationObserver/mutate-during-delivery.html:
* fast/dom/MutationObserver/mutation-callback-non-element-crash.html:
* fast/dom/MutationObserver/mutation-observer-constructor.html:
* fast/dom/MutationObserver/mutation-observer-prefix-expected.txt: Added.
* fast/dom/MutationObserver/mutation-observer-prefix.html: Added.
* fast/dom/MutationObserver/mutation-record-nullity.html:
* fast/dom/MutationObserver/observe-attributes.html:
* fast/dom/MutationObserver/observe-characterdata.html:
* fast/dom/MutationObserver/observe-childList.html:
* fast/dom/MutationObserver/observe-exceptions.html:
* fast/dom/MutationObserver/observe-subtree.html:
* fast/dom/MutationObserver/observer-wrapper-dropoff-transient.html:
* fast/dom/MutationObserver/observer-wrapper-dropoff.html:
* fast/dom/MutationObserver/parser-mutations.html:
* fast/dom/MutationObserver/removed-out-of-order.html:
* fast/dom/MutationObserver/shadow-dom.html:
* fast/dom/MutationObserver/takeRecords.html:
* fast/dom/MutationObserver/transient-gc-crash.html:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@143386 268f45cc-cd09-0410-ab3c-d52691b4dbfc