Move service worker into platform

src/vector/index.ts

@@ -29,11 +29,6 @@ require('katex/dist/katex.css');
 import {parseQsFromFragment} from "./url_utils";
 import './modernizr';
 
-// load service worker if available on this platform
-if (!window.electron && 'serviceWorker' in navigator) {
-    navigator.serviceWorker.register('sw.js');
-}
-
 async function settled(...promises: Array<Promise<any>>) {
     for (const prom of promises) {
         try {

src/vector/init.tsx

@@ -49,6 +49,8 @@ export function preparePlatform() {
         console.log("Using Web platform");
         PlatformPeg.set(new WebPlatform());
     }
+    // Register service worker if available on this platform
+    PlatformPeg.get().registerServiceWorker();
 }
 
 export async function loadConfig() {

src/vector/platform/WebPlatform.ts

@@ -38,6 +38,12 @@ export default class WebPlatform extends VectorBasePlatform {
         return 'Web Platform'; // no translation required: only used for analytics
     }
 
+    registerServiceWorker(): void {
+        if ('serviceWorker' in navigator) {
+            navigator.serviceWorker.register('sw.js');
+        }
+    }
+
     /**
      * Returns true if the platform supports displaying
      * notifications, otherwise false.