Replace -webkit-transform with transform in Chrome UI

ui/webui/resources/css/bubble.css

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 .bubble {
   position: absolute;
   white-space: normal;
   /* Height is dynamic, width fixed. */
   width: 300px;
   z-index: 9999;
@@ skipping 50 matching lines @@
   bottom: 0;
   box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
   left: 0;
   position: absolute;
   right: 0;
   top: 0;
   z-index: 1;
 }
 
 .bubble-arrow {
-  -webkit-transform: rotate(45deg);
+  transform: rotate(45deg);
   box-shadow: 1px 1px 6px rgba(0, 0, 0, 0.15);
   height: 15px;
   position: absolute;
   width: 15px;
   z-index: 2;
 }
 
 .bubble-content,
 .bubble-arrow {
   background: white;
 }
 
 .bubble-shadow,
 .bubble-arrow {
   border: 1px solid rgba(0, 0, 0, 0.3);
 }
 
 .bubble-shadow,
 .bubble-content {
   border-radius: 6px;
   box-sizing: border-box;
 }
 
 .auto-close-bubble {
   position: fixed;
 }