implemented crypto polyfills for ms edge

app/main.js

@@ -1,10 +1,10 @@
+import 'fast-text-encoding'; // MS Edge support
 import 'fluent-intl-polyfill';
 import app from './routes';
 import locale from '../common/locales';
 import fileManager from './fileManager';
 import dragManager from './dragManager';
 import { canHasSend } from './utils';
-import assets from '../common/assets';
 import storage from './storage';
 import metrics from './metrics';
 import experiments from './experiments';
@@ -30,10 +30,7 @@ app.use((state, emitter) => {
     ) {
       unsupportedReason = 'outdated';
     }
-    if (/edge\/\d+/i.test(navigator.userAgent)) {
-      unsupportedReason = 'edge';
-    }
-    const ok = await canHasSend(assets.get('cryptofill.js'));
+    const ok = await canHasSend();
     if (!ok) {
       unsupportedReason = /firefox/i.test(navigator.userAgent)
         ? 'outdated'

app/utils.js

@@ -25,7 +25,7 @@ function loadShim(polyfill) {
   });
 }
 
-async function canHasSend(polyfill) {
+async function canHasSend() {
   try {
     const key = await window.crypto.subtle.generateKey(
       {
@@ -35,7 +35,6 @@ async function canHasSend(polyfill) {
       true,
       ['encrypt', 'decrypt']
     );
-
     await window.crypto.subtle.encrypt(
       {
         name: 'AES-GCM',
@@ -45,9 +44,23 @@ async function canHasSend(polyfill) {
       key,
       new ArrayBuffer(8)
     );
+    await window.crypto.subtle.importKey(
+      'raw',
+      window.crypto.getRandomValues(new Uint8Array(16)),
+      'PBKDF2',
+      false,
+      ['deriveKey']
+    );
+    await window.crypto.subtle.importKey(
+      'raw',
+      window.crypto.getRandomValues(new Uint8Array(16)),
+      'HKDF',
+      false,
+      ['deriveKey']
+    );
     return true;
   } catch (err) {
-    return loadShim(polyfill);
+    return false;
   }
 }
 
@@ -167,6 +180,7 @@ module.exports = {
   copyToClipboard,
   arrayToB64,
   b64ToArray,
+  loadShim,
   canHasSend,
   isFile,
   openLinksInNewTab