Changed history menu style to match new C++ menus

chrome/browser/resources/shared/css/menu.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. */
 
 menu {
   -webkit-box-shadow: 0 2px 4px rgba(0, 0, 0, .50);
   background: white;
+  border-radius: 2px;
   color: black;
   cursor: default;
   left: 0;
   margin: 0;
   outline: 1px solid rgba(0, 0, 0, 0.2);
   padding: 8px 0;
   position: fixed;
   white-space: nowrap;
   z-index: 3;
 }
@@ skipping 32 matching lines @@
 
 menu > [disabled] {
   color: rgba(0, 0, 0, .3);
 }
 
 menu > [hidden] {
   display: none;
 }
 
 menu > :not(hr)[selected] {
-  background-color: rgb(220, 229, 250);
+  background-color: rgba(0, 0, 0, .06);
 }
 
 menu > :not(hr)[selected]:active {
-  background-color: rgb(66, 109, 201);
-  color: #fff;
+  background-color: rgba(0, 0, 0, .06);
 }
 
 menu > [checked]::before {
   content: url('../images/checkbox_black.png');
   display: inline-block;
   height: 9px;
   margin: 0 5px;
   vertical-align: 50%;
   width: 9px;
 }
 
 menu > [checked] {
   -webkit-padding-start: 0;
 }
 
 menu > [selected][checked]:active::before {
   content: url('../images/checkbox_white.png');
 }
 
 /* TODO(zvorygin) menu > [shortcutText]::after - this selector is much better,
  * but it's buggy in current webkit revision, so I have to use [showShortcuts].
  */
 menu[showShortcuts] > ::after {
   -webkit-padding-start: 30px;
   color: #999;
   content: attr(shortcutText);
   float: right;
 }