Pointer Lock IDL tests
interface EventTarget {
};
interface Node : EventTarget {
};
interface Element : Node {
};
interface Document : Node {
};
interface Event {
};
interface MouseEvent : Event {
};
partial interface Element {
    void requestPointerLock ();
};
partial interface Document {
                attribute EventHandler? onpointerlockchange;
                attribute EventHandler? onpointerlockerror;
    readonly    attribute Element?      pointerLockElement;
    void exitPointerLock ();
};
partial interface MouseEvent {
    readonly    attribute long movementX;
    readonly    attribute long movementY;
};