Use server-generated deviceId

src/MatrixClientPeg.js

@@ -21,21 +21,11 @@ import utils from 'matrix-js-sdk/lib/utils';
 
 const localStorage = window.localStorage;
 
-function deviceId() {
-    // XXX: is Math.random()'s deterministicity a problem here?
-    var id = Math.floor(Math.random()*16777215).toString(16);
-    id = "W" + "000000".substring(id.length) + id;
-    if (localStorage) {
-        id = localStorage.getItem("mx_device_id") || id;
-        localStorage.setItem("mx_device_id", id);
-    }
-    return id;
-}
-
 interface MatrixClientCreds {
     homeserverUrl: string,
     identityServerUrl: string,
     userId: string,
+    deviceId: string,
     accessToken: string,
     guest: boolean,
 }
@@ -87,6 +77,7 @@ class MatrixClientPeg {
             homeserverUrl: this.matrixClient.baseUrl,
             identityServerUrl: this.matrixClient.idBaseUrl,
             userId: this.matrixClient.credentials.userId,
+            deviceId: this.matrixClient.getDeviceId(),
             accessToken: this.matrixClient.getAccessToken(),
             guest: this.matrixClient.isGuest(),
         };
@@ -98,12 +89,12 @@ class MatrixClientPeg {
             idBaseUrl: creds.identityServerUrl,
             accessToken: creds.accessToken,
             userId: creds.userId,
+            deviceId: creds.deviceId,
             timelineSupport: true,
         };
 
         if (localStorage) {
             opts.sessionStore = new Matrix.WebStorageSessionStore(localStorage);
-            opts.deviceId = deviceId();
         }
 
         this.matrixClient = Matrix.createClient(opts);