[MR UI] Make custom controls / extensionview in the dialog taller by 6px

chrome/browser/resources/media_router/elements/route_details/route_details.css

 /* Copyright 2015 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. */
 
 
 #custom-controller {
   display: inline-block;
-  height: 136px;
+  height: 142px;
   width: 100%;
 }
 
 #route-action-buttons {
   @apply(--layout-horizontal);
   @apply(--layout-end-justified);
   margin: 0;
   padding: 0;
   white-space: nowrap;
 }
 
 .route-button {
   -webkit-padding-end: 24px;
   -webkit-padding-start: 0;
   background-color: white;
   line-height: 12px;
   margin: 12px 0;
   text-align: end;
 }
 
 #route-information {
   -webkit-padding-end: var(--dialog-padding-end);
   -webkit-padding-start: 44px;
   background-color: white;
   font-size: 1.2em;
   line-height: 1.5em;
   margin-top: 16px;
   overflow: hidden;
 }