Fix hover colour on network error blue button to white.

chrome/renderer/resources/neterror.css

 /* Copyright 2013 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. */
 
 body {
   background-color: #E6E6E6;
   font-family: Helvetica, Arial, sans-serif;
   font-size: 10pt;
   margin: 50px 40px 20px 40px;
 }
@@ skipping 176 matching lines @@
 <if expr="is_android">
   background-color: rgb(39, 180, 231);
   border: 1px solid rgb(0, 152, 206);
 </if>
 <if expr="not is_android and not is_ios">
   box-shadow: 0 1px 0 rgba(0, 0, 0, 0.15), inset 0 1px 2px rgba(255, 255, 255, 0.2);
 </if>
 }
 
 .blue-button:hover {
+  color: #fff;
 <if expr="not is_android">
   background-image: -webkit-linear-gradient(#659efd, #659efd 38%, #6097f1);
   border: 1px solid rgba(45, 102, 195, 1);
 </if>
 <if expr="not is_android and not is_ios">
   box-shadow: 0 1px 0 rgba(0, 0, 0, 0.25), inset 0 1px 2px rgba(255, 255, 255, 0.2);
 </if>
 }
 
 .blue-button:active {
@@ skipping 135 matching lines @@
   visibility: visible;
 }
 
 /* If the iframe is too small, always hide the error code. */
 /* TODO(mmenke): See if overflow: no-display works better, once supported. */
 @media (max-width: 200px), (max-height: 95px) {
   #sub-frame-error-details {
     display: none;
   }
 }