Added http header to BrowserFetchStreamTransport that bypasses servic…

…e worker onFetch implementation and lets the browser handle the request, specific to angular.

Background on root issue w3c/ServiceWorker#885
Issue leading to work around angular/angular#21191
Workaround that checks for the header petersalomonsen/angular@c7b357a

packages/browser/core/src/core/internal/net/BrowserFetchStreamTransport.ts

@@ -34,6 +34,10 @@ export default class BrowserFetchStreamTransport extends BrowserFetchTransport {
     const reqHeaders = { ...request.headers };
     reqHeaders[Headers.ACCEPT] = ContentTypes.TEXT_EVENT_STREAM;
     reqHeaders[Headers.CONTENT_TYPE] = ContentTypes.TEXT_EVENT_STREAM;
+    // Check for PWA and bypass service worker onFetch specific to angular service-worker.js
+    if ('ng' in window && 'serviceWorker' in navigator) {
+      reqHeaders['ngsw-bypass'] = true;
+    }
 
     // Verify we can start a request with current params and potentially
     // Force ourselves to refresh a token.