Use explicit case-insensitive attribute-value matching in UA-stylesheets

Source/core/css/mediaControls.css

 /*
  * Copyright (C) 2009 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 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 221 matching lines @@
     background-color: transparent;
     min-width: 15px;
     border: initial;
     color: inherit;
 }
 
 /* FIXME these shouldn't use special pseudoShadowIds, but nicer rules.
    https://code.google.com/p/chromium/issues/detail?id=112508
    https://bugs.webkit.org/show_bug.cgi?id=62218
 */
-input[type="range"]::-webkit-media-slider-container {
+input[type="range" i]::-webkit-media-slider-container {
     display: flex;
     align-items: center;
     flex-direction: row; /* This property is updated by C++ code. */
     box-sizing: border-box;
     height: 100%;
     width: 100%;
     border: 1px solid rgba(230, 230, 230, 0.35);
     border-radius: 4px;
     background-color: transparent; /* Background drawing is managed by C++ code to draw ranges. */
 }
 
 /* The negative right margin causes the track to overflow its container. */
-input[type="range"]::-webkit-media-slider-container > div {
+input[type="range" i]::-webkit-media-slider-container > div {
     margin-right: -14px;
 }
 
-input[type="range"]::-webkit-media-slider-thumb {
+input[type="range" i]::-webkit-media-slider-thumb {
     margin-left: -7px;
     margin-right: -7px;
 }
 
 audio::-webkit-media-controls-fullscreen-button, video::-webkit-media-controls-fullscreen-button {
     -webkit-appearance: media-enter-fullscreen-button;
     display: flex;
     flex: none;
     border: none;
     box-sizing: border-box;
@@ skipping 108 matching lines @@
     font-weight: bold;
 }
 
 video::-webkit-media-text-track-container u {
     text-decoration: underline;
 }
 
 video::-webkit-media-text-track-container i {
     font-style: italic;
 }