Allow notifications and actions to specify a navigable URL

This makes notifications more declarative by not requiring explicit handling of the clicks by the web application.

This is part of the Declarative Web Push effort: w3c/push-api#360.

notifications.bs

@@ -60,6 +60,9 @@ or "<code>rtl</code>").
 <p>A <a for=/>notification</a> has an associated <dfn for=notification id=body>body</dfn> (a
 string).
 
+<p>A <a for=/>notification</a> has an associated <dfn export for=notification>navigation URL</dfn>
+(null or a <a for=/>URL</a>). It is initially null.
+
 <p>A <a for=/>notification</a> has an associated <dfn for=notification id=tag>tag</dfn> (a string).
 
 <p>A <a for=/>notification</a> has an associated <dfn for=notification id=data>data</dfn> (a
@@ -137,6 +140,9 @@ support these features might ignore them.
  <dt><dfn for="notification action" id=action-title>title</dfn>
  <dd>A string.
 
+ <dt><dfn export for="notification action">navigation URL</dfn>
+ <dd>Null or a <a for=/>URL</a>. It is initially null.
+
  <dt><dfn for="notification action" id=action-icon-url>icon URL</dfn>
  <dd>Null or a <a for=/>URL</a>. It is initially null.
 
@@ -220,6 +226,11 @@ important information through, e.g., loss of color or clipped corners.
  <li><p>Set <var>notification</var>'s <a for=notification>body</a> to
  <var>options</var>["{{NotificationOptions/body}}"].
 
+ <li><p>If <var>options</var>["{{NotificationOptions/navigate}}"] <a for=map>exists</a>, then
+ <a lt="URL parser">parse</a> it using <var>baseURL</var>, and if that does not return failure, set
+ <var>notification</var>'s <a for=notification>navigation URL</a> to the return value. (Otherwise
+ <var>notification</var>'s <a for=notification>navigation URL</a> remains null.)
+
  <li><p>Set <var>notification</var>'s <a for=notification>tag</a> to
  <var>options</var>["{{NotificationOptions/tag}}"].
 
@@ -270,6 +281,11 @@ important information through, e.g., loss of color or clipped corners.
    <li><p>Set <var>action</var>'s <a for="notification action">title</a> to
    <var>entry</var>["{{NotificationAction/title}}"].
 
+   <li><p>If <var>entry</var>["{{NotificationAction/navigate}}"] <a for=map>exists</a>, then
+   <a lt="URL parser">parse</a> it using <var>baseURL</var>, and if that does not return failure,
+   set <var>action</var>'s <a for="notification action">navigation URL</a> to the return value.
+   (Otherwise <var>action</var>'s <a for="notification action">navigation URL</a> remains null.)
+
    <li><p>If <var>entry</var>["{{NotificationAction/icon}}"] <a for=map>exists</a>, then
    <a lt="URL parser">parse</a> it using <var>baseURL</var>, and if that does not return failure,
    set <var>action</var>'s <a for="notification action">icon URL</a> to the return value. (Otherwise
@@ -541,18 +557,51 @@ interpreted as a language tag. Validity or well-formedness are not enforced. [[!
 platform supports activation, the user agent must (unless otherwise specified) run these steps:
 
 <ol>
+ <li><p>Let <var>action</var> be null.
+
+ <li><p>If one of <var>notification</var>'s <a for=notification>actions</a> was activated by the end
+ user, then set <var>action</var> to that <a for=/>action</a>.
+
+ <li><p>Let <var>navigationURL</var> be <var>notification</var>'s
+ <a for=notification>navigation URL</a>.
+
+ <li>
+  <p>If <var>action</var> is non-null, then set <var>navigationURL</var> to <var>action</var>'s
+  <a for="notification action">navigation URL</a>.
+
+  <p class=note>This intentionally makes it so that when an <a for=/>action</a>'s
+  <a for="notification action">navigation URL</a> is null, it falls through to the
+  <code>click</code> event, providing more flexibility to the web developer.
+
+ <li>
+  <p>If <var>navigationURL</var> is non-null:
+
+  <ol>
+   <li><p>If there is an existing <a for=/>top-level traversable</a> <var>traversable</var> within
+   the user agent's <a for="user agent">top-level traversable set</a> whose
+   <a for="navigable">active document</a>'s <a for=Document>URL</a> <a for=url>equals</a>
+   <var>navigationURL</var> with <a for=url/equals><i>exclude fragments</i></a> set to true, then
+   <a for=/>navigate</a> <var>traversable</var> to <var>navigationURL</var> and return. If there are
+   multiple <a for=/>top-level traversables</a> that satisfy the condition the user agent has to
+   pick one in an <a>implementation-defined</a> manner.
+   <!-- Should maybe set userInvolvement correctly here and below. -->
+
+   <li><p><a>Create a fresh top-level traversable</a> given <var>navigationURL</var>.
+
+   <li><p>Return.
+  </ol>
+
  <li>
   <p>If <var>notification</var> is a <a>persistent notification</a>, then:
 
   <ol>
-   <li><p>Let <var>action</var> be the empty string.
+   <li><p>Let <var>actionName</var> be the empty string.
 
-   <li><p>If one of <var>notification</var>'s <a for=notification>actions</a> was activated by the
-   user, then set <var>action</var> to that <a for=/>notification action</a>'s
+   <li><p>If <var>action</var> is non-null, then set <var>actionName</var> to <var>action</var>'s
    <a for="notification action">name</a>.
 
    <li><a>Fire a service worker notification event</a> named "<code>notificationclick</code>" given
-   <var>notification</var> and <var>action</var>.
+   <var>notification</var> and <var>actionName</var>.
   </ol>
 
  <li>
@@ -643,6 +692,7 @@ interface Notification : EventTarget {
   readonly attribute NotificationDirection dir;
   readonly attribute DOMString lang;
   readonly attribute DOMString body;
+  readonly attribute USVString navigate;
   readonly attribute DOMString tag;
   readonly attribute USVString image;
   readonly attribute USVString icon;
@@ -662,6 +712,7 @@ dictionary NotificationOptions {
   NotificationDirection dir = "auto";
   DOMString lang = "";
   DOMString body = "";
+  USVString navigate;
   DOMString tag = "";
   USVString image;
   USVString icon;
@@ -690,6 +741,7 @@ enum NotificationDirection {
 dictionary NotificationAction {
   required DOMString action;
   required DOMString title;
+  USVString navigate;
   USVString icon;
 };
 
@@ -853,6 +905,16 @@ return the <a>maximum number of actions</a> supported.
 <p>The <dfn attribute for=Notification><code>body</code></dfn> getter steps are to return
 <a>this</a>'s <a for=/>notification</a>'s <a for=notification>body</a>.
 
+<p>The <dfn attribute for=Notification><code>navigate</code></dfn> getter steps are:
+
+<ol>
+ <li><p>If <a>this</a>'s <a>notification</a>'s <a for=notification>navigation URL</a> is null, then
+ return the empty string.
+
+ <li><p>Return <a>this</a>'s <a>notification</a>'s <a for=notification>navigation URL</a>,
+ <a lt="URL serializer">serialized</a>.
+</ol>
+
 <p>The <dfn attribute for=Notification><code>tag</code></dfn> getter steps are to return
 <a>this</a>'s <a for=/>notification</a>'s <a for=notification>tag</a>.
 
@@ -925,6 +987,10 @@ then return null.
    <li><p>Set <var>action</var>["{{NotificationAction/title}}"] to <var>entry</var>'s
    <a for="notification action">title</a>.
 
+   <li><p>If <var>entry</var>'s <a for="notification action">navigation URL</a> is non-null, then
+   set <var>action</var>["{{NotificationAction/navigate}}"] to <var>entry</var>'s
+   <a for="notification action">navigation URL</a>, <a lt="URL serializer">serialized</a>.
+
    <li><p>If <var>entry</var>'s <a for="notification action">icon URL</a> is non-null, then set
    <var>action</var>["{{NotificationAction/icon}}"] to <var>entry</var>'s
    <a for="notification action">icon URL</a>, <a lt="URL serializer">serialized</a>.