Media Remoting: Add interstitial elements to media element shadow dom.

third_party/WebKit/Source/core/css/mediaControls.css

 /*
  * Copyright (C) 2009 Apple Inc.  All rights reserved.
  * Copyright (C) 2015 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 31 matching lines @@
     height: inherit;
     position: relative;
     direction: ltr;
     display: flex;
     flex-direction: column;
     font-family: Segoe, "Helvetica Neue", Roboto, Arial, Helvetica, sans-serif;
     justify-content: flex-end;
     align-items: center;
 }
 
+audio::-webkit-media-remoting-interstitial,
+video::-webkit-media-remoting-interstitial {
+    width: inherit;
+    height: inherit;
+    position: relative;
+    direction: ltr;
+    display: flex;
+    flex-direction: column;
+    font-family: Segoe, "Helvetica Neue", Roboto, Arial, Helvetica, sans-serif;
+    justify-content: flex-end;
+    align-items: center;
+}
+
 audio::-webkit-media-controls-enclosure, video::-webkit-media-controls-enclosure {
     width: 100%;
     height: 32px;
     flex-shrink: 0;
     bottom: 0;
     text-indent: 0;
     padding: 0;
     margin: 0;
     box-sizing: border-box;
 }
@@ skipping 76 matching lines @@
     top: 0;
     left: 0;
     margin: 0;
     border-width: 0px;
     background-color: transparent;
     width: 100%;
     height: 100%;
     padding: 0;
 }
 
+video::-webkit-media-remoting-disable-button {
+    -webkit-appearance: media-remoting-disable-button;
+    display: flex;
+    position: absolute;
+    margin: 0;
+    top: 28%;
+    left: 53%;
+    border-width: 0px;
+    background-color: transparent;
+    width: 48px;
+    height: 48px;
+    padding: 0;
+}
+
 video::-internal-media-controls-overlay-cast-button {
     -webkit-appearance: -internal-media-overlay-cast-off-button;
     display: flex;
     position: absolute;
     top: 8px;
     left: 8px;
     margin-left: 0px;
     margin-top: 0px;
     border-width: 0px;
     background-color: transparent;
@@ skipping 356 matching lines @@
     font-weight: bold;
 }
 
 video::cue(u) {
     text-decoration: underline;
 }
 
 video::cue(i) {
     font-style: italic;
 }