WakeLock.request(): Check page visibility in the queued task.

This should allow us to avoid requesting a lock in case there has been a
visibility change between obtaining permission and the subsequent steps.

index.html

@@ -51,6 +51,7 @@
         xref: {
           profile: "web-platform",
           specs: [
+            "page-visibility",
             "permissions",
             "permissions-policy",
           ]
@@ -364,9 +365,10 @@ <h3>
           |document| is not [=Document/fully active=], return [=a promise
           rejected with=] with a {{"NotAllowedError"}} {{DOMException}}.
           </li>
-          <li data-tests="wakelock-document-hidden-manual.https.html">If
-          |document| is <a>hidden</a>, return [=a promise rejected with=]
-          {{"NotAllowedError"}} {{DOMException}}.
+          <li data-tests="wakelock-document-hidden-manual.https.html">If the
+          steps to <a>determine the visibility state</a> return `hidden`,
+          return [=a promise rejected with=] {{"NotAllowedError"}}
+          {{DOMException}}.
           </li>
           <li>Let |record| be the <a>platform wake lock</a>'s <a>state
           record</a> associated with |document| and |type|.
@@ -375,11 +377,6 @@ <h3>
           </li>
           <li>Run the following steps <a>in parallel</a>:
             <ol>
-              <!--
-              <li>
-                <a>Abort when</a> |document| is <a>hidden</a>.
-              </li>
-              -->
               <li>Let |state:PermissionState| be the result of awaiting
               <a>obtain permission</a> steps with "`screen-wake-lock`":
                 <ol>
@@ -396,6 +393,10 @@ <h3>
                 <a>Queue a global task</a> on the <a>screen wake lock task
                 source</a> given |global| to run these steps:
                 <ol>
+                  <li>If the steps to <a>determine the visibility state</a>
+                  return `hidden`, reject |promise| with a
+                  {{"NotAllowedError"}} {{DOMException}}.
+                  </li>
                   <li>If |record|.{{[[ActiveLocks]]}} is [=list/empty=], then
                   invoke the following steps <a>in parallel</a>:
                     <ol>