media_controls: Add UI for showing a promo bubble on a control button.

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 54 matching lines @@
     flex-direction: row;
     align-items: center;
     /* We use flex-start here to ensure that the play button is visible even
      * if we are too small to show all controls.
      */
     justify-content: flex-start;
     -webkit-user-select: none;
     position: relative;
     width: 100%;
     z-index: 0;
-    overflow: hidden;
+    overflow: visible;
     text-align: right;
     bottom: auto;
     height: 32px;
     min-width: 48px;
     line-height: 32px;
     background-color: #fafafa;
     /* The duration is also specified in MediaControlElements.cpp and LayoutTests/media/media-controls.js */
     transition: opacity 0.3s;
 
     font-size: 12px;
@@ skipping 420 matching lines @@
     width: 32px;
     height: 32px;
     padding: 0px;
     border-width: 0px;
     margin-left: 0px;
     margin-right: 0px;
     background-color: initial;
     color: inherit;
 }
 
+video::-internal-media-controls-download-button-container, audio::-internal-media-controls-download-button-container {
+    display: flex;
+    flex: none;
+    position: relative;
+    box-sizing: border-box;
+    width: 32px;
+    height: 32px;
+    background-color: initial;
+    color: inherit;
+}
+
 video::-internal-media-controls-download-button, audio::-internal-media-controls-download-button {
     -webkit-appearance: -internal-media-download-button;
     display: flex;
     flex: none;
     box-sizing: border-box;
-    width: 32px;
-    height: 32px;
+    width: inherit;
+    height: inherit;
     padding: 0px;
     border-width: 0px;
     margin-left: 0px;
     margin-right: 0px;
     background-color: initial;
     color: inherit;
 }
 
 video::-internal-media-controls-overflow-menu-list-item, audio::-internal-media-controls-overflow-menu-list-item {
     display: block;
@@ skipping 69 matching lines @@
     font-weight: bold;
 }
 
 video::cue(u) {
     text-decoration: underline;
 }
 
 video::cue(i) {
     font-style: italic;
 }
+
+video::-internal-media-controls-promo-container {
+    display: flex;
+    flex: none;
+    position: absolute;
+    left: 0px;
+    top: 0px;
+    box-sizing: border-box;
+    z-index: 42;
+    width: inherit;
+    height: inherit;
+    background-color: initial;
+    color: inherit;
+    pointer-events: none;
+}
+
+@keyframes -internal-media-controls-promo-throbbing {
+    0%    {transform: scale(0.5, 0.5);}
+    50%   {transform: scale(1.0, 1.0);}
+    100%  {transform: scale(0.5, 0.5);}
+}
+
+video::-internal-media-controls-promo-animation {
+    display: flex;
+    flex: none;
+    box-sizing: border-box;
+    width: inherit;
+    height: inherit;
+    border-radius: 50%;
+    background-color: #4285f4;
+    color: blue;
+    opacity: 0.4;
+    animation: -internal-media-controls-promo-throbbing 2s infinite;
+}
+
+video::-internal-media-controls-promo-arrow {
+    display: flex;
+    flex: none;
+    box-sizing: border-box;
+    position: absolute;
+    top: 100%;
+    left: 50%;
+    margin-left: -10px;
+    margin-top: -10px;
+    width: 0px;
+    height: 0px;
+    border-top: 10px solid transparent;
+    border-left: 10px solid transparent;
+    border-right: 10px solid transparent;
+    border-bottom: 10px solid #4285f4;
+}
+
+video::-internal-media-controls-promo-text {
+    display: inline-block;
+    flex: none;
+    position: absolute;
+    background: #5285f4;
+    color: #fff;
+    font-family: sans-serif;
+    padding: 16px;
+    top: 100%;
+    right: 0%;
+    margin-top: 10px;
+    z-index: 42;
+    border-radius: 2px;
+    font-size: 14px;
+    color: white;
+    white-space: nowrap;
+    line-height: 100%;
+}