Introduce a generic skip action as a replacement to skipad.

Introduce a media kind to allow marking content as either advertisement, generic and so on.

index.bs

@@ -371,8 +371,8 @@ platform UI or media keys, thereby improving the user experience.
           the playback has a notion of playlist.
         </li>
         <li>
-          <dfn enum-value for=MediaSessionAction>skipad</dfn>: the action's
-          intent is to skip the advertisement that is currently playing.
+          <dfn enum-value for=MediaSessionAction>skip</dfn>: the action's
+          intent is to skip the media item that is currently playing.
         </li>
         <li>
           <dfn enum-value for=MediaSessionAction>stop</dfn>: the action's intent
@@ -740,7 +740,7 @@ enum MediaSessionAction {
   "seekforward",
   "previoustrack",
   "nexttrack",
-  "skipad",
+  "skip",
   "stop",
   "seekto",
   "togglemicrophone",
@@ -1066,6 +1066,7 @@ interface MediaMetadata {
   attribute DOMString title;
   attribute DOMString artist;
   attribute DOMString album;
+  readonly attribute MediaKind kind;
   attribute FrozenArray&lt;object> artwork;
   [SameObject] readonly attribute FrozenArray&lt;ChapterInformation> chapterInfo;
 };
@@ -1074,9 +1075,18 @@ dictionary MediaMetadataInit {
   DOMString title = "";
   DOMString artist = "";
   DOMString album = "";
+  MediaKind kind = "";
   sequence&lt;MediaImage> artwork = [];
   sequence&lt;ChapterInformationInit> chapterInfo = [];
 };
+
+enum MediaKind {
+  "advertisement",
+  "generic",
+  "pregeneric",
+  "summary",
+  ""
+};
 </pre>
 
 <p>
@@ -1096,6 +1106,11 @@ dictionary MediaMetadataInit {
   which are DOMString.
 </p>
 
+<p>
+  A {{MediaMetadata}} has an associated <dfn for="MediaMetadata">kind</dfn>,
+  which is a {{MediaKind}}.
+</p>
+
 <p>
   A {{MediaMetadata}} has an associated sequence of <dfn
   for="MediaMetadata">artwork images</dfn>, which is a sequence of type
@@ -1116,6 +1131,7 @@ dictionary MediaMetadataInit {
     <li>Its <a for=MediaMetadata>title</a> is the empty string.</li>
     <li>Its <a for=MediaMetadata>artist</a> is the empty string.</li>
     <li>Its <a for=MediaMetadata>album</a> is the empty string.</li>
+    <li>Its <a for=MediaMetadata>kind</a> is the empty string.</li>
     <li>Its <a for=MediaMetadata title='artwork image'>artwork images</a> length
     is <code>0</code>.</li>
     <li>Its <a for=MediaMetadata>chapter information</a> length is
@@ -1143,6 +1159,10 @@ dictionary MediaMetadataInit {
       Set <var>metadata</var>'s {{MediaMetadata/album}} to
       <var>init</var>'s {{MediaMetadataInit/album}}.
     </li>
+    <li>
+      Set <var>metadata</var>'s {{MediaMetadata/kind}} to
+      <var>init</var>'s {{MediaMetadataInit/kind}}.
+    </li>
     <li>
       Run the <a>convert artwork algorithm</a> with <var>init</var>'s
       {{MediaMetadataInit/artwork}} as <var>input</var> and set
@@ -1231,6 +1251,11 @@ user agent MUST run the following steps:
   set the {{MediaMetadata}}'s <a for=MediaMetadata>album</a> to the given value.
 </p>
 
+<p>
+  The <dfn attribute for="MediaMetadata">kind</dfn> attribute reflects the
+  {{MediaMetadata}}'s <a for=MediaMetadata>kind</a>. On getting, it MUST return
+  the {{MediaMetadata}}'s <a for=MediaMetadata>kind</a>.</p>
+
 <p>
   The <dfn attribute for="MediaMetadata">artwork</dfn>
   attribute reflects the {{MediaMetadata}}'s <a for="MediaMetadata">artwork
@@ -1329,12 +1354,14 @@ interface</h2>
 interface ChapterInformation {
   readonly attribute DOMString title;
   readonly attribute double startTime;
+  readonly attribute MediaKind kind;
   [SameObject] readonly attribute FrozenArray&lt;MediaImage> artwork;
 };
 
 dictionary ChapterInformationInit {
   DOMString title = "";
   double startTime = 0;
+  MediaKind kind = "";
   sequence&lt;MediaImage> artwork = [];
 };
 
@@ -1363,6 +1390,12 @@ dictionary ChapterInformationInit {
   startTime</dfn> which is double.
 </p>
 
+<p>
+  A {{ChapterInformation}} has an associated <dfn
+  for="ChapterInformation">kind</dfn>
+  which is a {{MediaKind}}.
+</p>
+
 <p>
   A {{ChapterInformation}} has an associated list of <dfn
   for="ChapterInformation">
@@ -1387,6 +1420,10 @@ dictionary ChapterInformationInit {
       for=ChapterInformation>startTime</a> is negative or greater than
       [=duration=], throw a <a exception>TypeError</a>.
     </li>
+    <li>
+      Set <var>chapterInfo</var>'s {{ChapterInformation/kind}} to
+      <var>init</var>'s {{ChapterInformationInit/kind}}.
+    </li>
     <li>
       Let {{ChapterInformationInit/artwork}} be the result of running the
       <a>convert artwork algorithm</a> with <var>init</var>'s
@@ -1416,6 +1453,12 @@ dictionary ChapterInformationInit {
   for=ChapterInformation>startTime</a>.
 </p>
 
+<p>
+  The <dfn attribute for="ChapterInformation">kind</dfn> attribute reflects the
+  {{ChapterInformation}}'s <a for=ChapterInformation>kind</a>. On getting, it
+  MUST return the {{ChapterInformation}}'s <a for=ChapterInformation>kind</a>.
+</p>
+
 <p>
   The <dfn attribute for="ChapterInformation">artwork</dfn>
   attribute reflects the {{ChapterInformation}}'s <a