Revert "Fix IE11 broken by Crypto change. (#2832)"

This reverts commit 353f5ca.

Author: dconeybe

packages/firestore/src/platform_browser/browser_platform.ts

@@ -25,10 +25,6 @@ import { NoopConnectivityMonitor } from '../remote/connectivity_monitor_noop';
 import { BrowserConnectivityMonitor } from './browser_connectivity_monitor';
 import { WebChannelConnection } from './webchannel_connection';
 
-// Polyfill for IE
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-const crypto = window.crypto || (window as any).msCrypto;
-
 export class BrowserPlatform implements Platform {
   readonly useProto3Json = true;
   readonly base64Available: boolean;

packages/firestore/src/util/misc.ts

@@ -31,15 +31,15 @@ export class AutoId {
     let autoId = '';
     while (autoId.length < 20) {
       const bytes = PlatformSupport.getPlatform().randomBytes(40);
-      for (const b of Array.from(bytes)) {
+      bytes.forEach(b => {
         // Length of `chars` is 62. We only take bytes between 0 and 62*4-1
         // (both inclusive). The value is then evenly mapped to indices of `char`
         // via a modulo operation.
         const maxValue = 62 * 4 - 1;
         if (autoId.length < 20 && b <= maxValue) {
           autoId += chars.charAt(b % 62);
         }
-      }
+      });
     }
     assert(autoId.length === 20, 'Invalid auto ID: ' + autoId);
     return autoId;