Convert Chromoting to use the new, non-deprecated flexbox

remoting/webapp/main.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.
  */
 
 html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p,
 blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em,
 font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, dl,
 dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody,
 tfoot, thead, tr, th, td, button {
@@ skipping 229 matching lines @@
   font-weight: normal;
   color: #222;
   margin-bottom: 10px;
 }
 
 section > h2 {
   color: #666;
 }
 
 header {
-  display: -webkit-box;
+  display: -webkit-flex;
   width: 100%;
 }
 
 html {
   -webkit-user-select: none;
   cursor: default;
 }
 
 section {
   width: 690px;
@@ skipping 11 matching lines @@
 
 .access-code-digit-group {
   /*
     Used for each of the four-digit components of the access code as
     displayed by the host.
   */
   padding: 0px 6px;
 }
 
 .box-spacer {
-  -webkit-box-flex: 1;
+  -webkit-flex: 1;
 }
 
 .centered {
   text-align: center;
 }
 
 .clickable {
   cursor: pointer;
 }
 
 .box {
-  display: -webkit-box;
+  display: -webkit-flex;
 }
 
 .host-list-empty-instructions {
   padding-__MSG_@@bidi_start_edge__: 36px;
   color: #666;
   background-image: url('host_setup_instructions.webp');
   background-repeat: no-repeat;
   background-position: -3px -2px;
 }
 
 #host-list-empty-hosting-supported {
   margin-top: 14px;
   padding-top: 20px;
   border-top: 1px solid #E5E5E5;
   background-position-y: 18px;
 }
 
 .selectable {
   -webkit-user-select: text;
   cursor: text;
 }
 
 .section-row {
-  display: -webkit-box;
-  -webkit-box-align: center;
+  display: -webkit-flex;
+  -webkit-align-items: center;
   padding: 10px 0;
   border-top: 1px solid #EBEBEB;
 }
 
 .section-row button {
   margin-__MSG_@@bidi_start_edge__: 20px;
 }
 
 .section-row:first-child,
 .section-row.no-non-local-hosts {
@@ skipping 197 matching lines @@
 #daemon-plugin-container {
   width: 0;
   height: 0;
 }
 
 .dialog-container {
   position: fixed;
   top: 200px;
   left: 0;
   width: 100%;
-  display: -webkit-box;
+  display: -webkit-flex;
 }
 
 .dialog-screen {
   position: fixed;
   top: 0;
   left: 0;
   width: 100%;
   height: 100%;
   background-color: #fff;
   opacity: 0.75;
@@ skipping 49 matching lines @@
   box-sizing: border-box;
 }
 
 /*
  * Setting hidden on elements that match some rule overriding 'display' doesn't
  * do what you would expect unless this is made explicit (and !important).
  */
 [hidden] {
   display: none !important;
 }