Permissions API changes

gistfile1.js

interface PermissionStatus : EventTarget {
    readonly attribute PermissionState status;
             attribute EventHandler onchange;
};

dictionary PermissionOptions {
};

interface Permission {
    Promise<PermissionStatus> query(optional PermissionOptions options);
};

interface Permissions {
    readonly attribute GeolocationPermission geolocation;
    readonly attribute MidiPermission midi;
    readonly attribute NotificationsPermission notifications;
    readonly attribute PushPermission push;
};

// Geolocation
interface GeolocationPermission : Permission {
};

// Midi
dictionary MidiPermissionOptions : PermissionOptions {
    boolean sysex = false;
};
interface MidiPermission : Permission {
    Promise<PermissionStatus> query(optional MidiPermissionOptions options);
};

// Notifications
interface NotificationsPermission : Permission {
};

// Push
dictionary PushPermissionOptions : PermissionOptions {
    boolean userVisible = false;
};
interface PushPermission : Permission {
    Promise<PermissionStatus> query(optional PushPermissionOptions options);
};