Add new Pointer Lock spec webkitRequestPointerLock and webkitExitPointerLock methods.

https://bugs.webkit.org/show_bug.cgi?id=88891

Reviewed by Dimitri Glazkov.

Part of a series of refactoring changes to update pointer lock API to
the fullscreen locking style. https://bugs.webkit.org/show_bug.cgi?id=84402

Entering and exiting mouse lock is provided in the new webkitRequestPointerLock and
webkitExitPointerLock methods.

Source/WebCore:

Existing pointer-lock tests updated to use the new methods.

* dom/Document.cpp:
(WebCore::Document::webkitExitPointerLock):
(WebCore):
* dom/Document.h:
(Document):
* dom/Document.idl:
* dom/Element.cpp:
(WebCore):
(WebCore::Element::webkitRequestPointerLock):
* dom/Element.h:
* dom/Element.idl:

LayoutTests:

Existing tests updated to use the new methods. Also, several updated to
support manual testing.

* pointer-lock/lock-already-locked-expected.txt:
* pointer-lock/lock-already-locked.html:
* pointer-lock/mouse-event-delivery-expected.txt:
* pointer-lock/mouse-event-delivery.html:
* pointer-lock/pointer-lock-api-expected.txt:
* pointer-lock/pointer-lock-api.html:
* pointer-lock/pointerlockchange-pointerlockerror-events-expected.txt:
* pointer-lock/pointerlockchange-pointerlockerror-events.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@120486 268f45cc-cd09-0410-ab3c-d52691b4dbfc