Use abstract class instead of interface for ReceiverSelector base

ext/src/background/receiverSelector/NativeReceiverSelector.ts

@@ -12,17 +12,13 @@ import { Receiver } from "../../types";
 
 import ReceiverSelector, {
         ReceiverSelection
-      , ReceiverSelectorEvents
       , ReceiverSelectorMediaType } from "./ReceiverSelector";
 
 
 const _ = browser.i18n.getMessage;
 
 // TODO: Figure out lifetime properly
-export default class NativeReceiverSelector
-        extends TypedEventTarget<ReceiverSelectorEvents>
-        implements ReceiverSelector {
-
+export default class NativeReceiverSelector extends ReceiverSelector {
     private bridgePort: (Port | null) = null;
     private wasReceiverSelected: boolean = false;
     private _isOpen: boolean = false;

ext/src/background/receiverSelector/PopupReceiverSelector.ts

@@ -1,8 +1,7 @@
 "use strict";
 
 import ReceiverSelector, {
-        ReceiverSelectorEvents
-      , ReceiverSelectorMediaType } from "./ReceiverSelector";
+        ReceiverSelectorMediaType } from "./ReceiverSelector";
 
 import logger from "../../lib/logger";
 import messaging, { Port, Message } from "../../lib/messaging";
@@ -15,10 +14,7 @@ import { Receiver } from "../../types";
 
 const POPUP_URL = browser.runtime.getURL("ui/popup/index.html");
 
-export default class PopupReceiverSelector
-        extends TypedEventTarget<ReceiverSelectorEvents>
-        implements ReceiverSelector {
-
+export default class PopupReceiverSelector extends ReceiverSelector {
     private windowId?: number;
 
     private messagePort?: Port;

ext/src/background/receiverSelector/ReceiverSelector.ts

@@ -30,22 +30,22 @@ export interface ReceiverSelectionStop {
 export type ReceiverSelection = ReceiverSelectionCast | ReceiverSelectionStop;
 
 
-export interface ReceiverSelectorEvents {
+interface ReceiverSelectorEvents {
     "selected": ReceiverSelectionCast;
     "error": string;
     "cancelled": void;
     "stop": ReceiverSelectionStop;
 }
 
-export default interface ReceiverSelector
+export default abstract class ReceiverSelector
         extends TypedEventTarget<ReceiverSelectorEvents> {
 
-    readonly isOpen: boolean;
+    abstract readonly isOpen: boolean;
 
-    open (receivers: Receiver[]
+    abstract open (receivers: Receiver[]
         , defaultMediaType: ReceiverSelectorMediaType
         , availableMediaTypes: ReceiverSelectorMediaType
         , requestedAppId: string): void;
 
-    close (): void;
+    abstract close (): void;
 }