Use phosphorjs to generate the UUID instead of our own code.

packages/base/src/utils.ts

@@ -5,6 +5,10 @@ import {
     toByteArray, fromByteArray
 } from 'base64-js';
 
+import {
+    UUID
+} from '@phosphor/coreutils';
+
 import _isEqual = require('lodash/isEqual');
 import isPlainObject = require('lodash/isPlainObject');
 
@@ -40,19 +44,13 @@ let assign = (Object as any).assign || function(t) {
 };
 
 /**
+ * Generate a UUID
+ *
  * http://www.ietf.org/rfc/rfc4122.txt
  */
 export
 function uuid(): string {
-    let s = [];
-    const hexDigits = '0123456789ABCDEF';
-    for (let i = 0; i < 32; i++) {
-        s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
-    }
-    s[12] = '4';  // bits 12-15 of the time_hi_and_version field to 0010
-    s[16] = hexDigits.substr((s[16] & 0x3) | 0x8, 1);  // bits 6-7 of the clock_seq_hi_and_reserved to 01
-
-    return s.join('');
+    return UUID.uuid4();
 }
 
 /**