Paint media element's play button using padding.

third_party/WebKit/Source/core/css/mediaControlsAndroidNew.css

 /*
  * 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
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 /* Media controls for Chromium on Android */
 
 /* WARNING: This css file can only style <audio> and <video> elements */
 
+audio {
+    height: 48px;
+}
+
+audio::-webkit-media-controls-enclosure, video::-webkit-media-controls-enclosure {
+    height: 48px;
+}
+
+audio::-webkit-media-controls-panel, video::-webkit-media-controls-panel {
+    height: 48px;
+    min-width: 48px;
+    line-height: 48px;
+    font-size: 14px;
+}
+
+audio::-webkit-media-controls-mute-button, video::-webkit-media-controls-mute-button {
+    padding: 8px;
+}
+
+video::-internal-media-controls-overlay-cast-button {
+    width: 48px;
+    height: 48px;
+}
+
+audio::-webkit-media-controls-play-button, video::-webkit-media-controls-play-button {
+    padding: 8px;
+}
+
+audio::-webkit-media-controls-timeline-container, video::-webkit-media-controls-timeline-container {
+    height: 48px;
+}
+
+audio::-webkit-media-controls-current-time-display, video::-webkit-media-controls-current-time-display {
+    height: 48px;
+}
+
+audio::-webkit-media-controls-time-remaining-display, video::-webkit-media-controls-time-remaining-display {
+    height: 48px;
+}
+
+audio::-webkit-media-controls-fullscreen-button, video::-webkit-media-controls-fullscreen-button {
+    padding: 8px;
+}
+
+audio::-internal-media-controls-cast-button, video::-internal-media-controls-cast-button {
+    padding: 8px;
+}
+
+video::-webkit-media-controls-toggle-closed-captions-button {
+    padding: 8px;
+}