fix horizontal scrollbar flicker on uber page

chrome/browser/resources/uber/uber.css

Index: chrome/browser/resources/uber/uber.css
diff --git a/chrome/browser/resources/uber/uber.css b/chrome/browser/resources/uber/uber.css
index 467dee852c8edea20294820d3c7c88f6f149a2dd..76ba333dd3ad203af9f3b50ac667f1706d15d631 100644
--- a/chrome/browser/resources/uber/uber.css
+++ b/chrome/browser/resources/uber/uber.css
@@ -2,6 +2,12 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
+body {
+  /* http://crbug.com/129406 --- horizontal scrollbars flicker when changing
+   * sections. */
+  overflow-x: hidden;
+}
+
 #navigation {
   height: 100%;
   left: 0;