webkitRequestPointerLock and webkitExitPointerLock limited to the same...

webkitRequestPointerLock and webkitExitPointerLock limited to the same document of an active Pointer lock.
https://bugs.webkit.org/show_bug.cgi?id=91284

Reviewed by Adrienne Walker.

Previously, cross-talk between documents was possible, e.g. allowing one
document.webkitExitPointerLock to exit the lock from another document.
This change brings Pointer Lock closer to the Fullscreen API behavior,
and stops the pointer lock target from being transferable between
documents.

Source/WebCore:

Test: http/tests/pointer-lock/requestPointerLock-can-not-transfer-between-documents.html

* dom/Document.cpp:
(WebCore::Document::webkitExitPointerLock):
* page/PointerLockController.cpp:
(WebCore::PointerLockController::requestPointerLock):

LayoutTests:

* http/tests/pointer-lock/requestPointerLock-can-not-transfer-between-documents-expected.txt: Added.
* http/tests/pointer-lock/requestPointerLock-can-not-transfer-between-documents.html: Added.
* http/tests/resources/pointer-lock/iframe-common.js:
(document.onwebkitpointerlockchange):
(document.onwebkitpointerlockerror):
* pointer-lock/pointerlockchange-pointerlockerror-events-expected.txt:
* pointer-lock/pointerlockchange-pointerlockerror-events.html:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@124301 268f45cc-cd09-0410-ab3c-d52691b4dbfc