Adding preloadResponse to fetch event.

Author: jakearchibald

docs/index.bs

@@ -1837,6 +1837,7 @@ spec: webidl; urlPrefix: https://heycam.github.io/webidl/
       [Constructor(DOMString type, FetchEventInit eventInitDict), Exposed=ServiceWorker]
       interface FetchEvent : ExtendableEvent {
         [SameObject] readonly attribute Request request;
+        readonly attribute Promise<Response?> preloadResponse;
         readonly attribute DOMString? clientId;
         readonly attribute boolean isReload;
 
@@ -1846,6 +1847,7 @@ spec: webidl; urlPrefix: https://heycam.github.io/webidl/
     <pre class="idl" id="fetch-event-init-dictionary">
       dictionary FetchEventInit : ExtendableEventInit {
         required Request request;
+        required Promise&lt;Response?&gt; preloadResponse;
         DOMString? clientId = null;
         boolean isReload = false;
       };
@@ -1867,6 +1869,12 @@ spec: webidl; urlPrefix: https://heycam.github.io/webidl/
       <p><dfn attribute id="fetch-event-request-attribute"><code>request</code></dfn> attribute <em class="rfc2119" title="MUST">must</em> return the value it was initialized to.</p>
     </section>
 
+    <section>
+      <h4 id="fetch-event-preloadresponse">{{FetchEvent/preloadResponse|event.preloadResponse}}</h4>
+
+      <p><dfn attribute id="fetch-event-preloadresponse-attribute"><code>preloadResponse</code></dfn> attribute <em class="rfc2119" title="MUST">must</em> return the value it was initialized to.</p>
+    </section>
+
     <section>
       <h4 id="fetch-event-clientid">{{FetchEvent/clientId|event.clientId}}</h4>
 
@@ -3717,7 +3725,7 @@ spec: webidl; urlPrefix: https://heycam.github.io/webidl/
       <li>Let <var>response</var> be null.</li>
       <li>Let <var>registration</var> be null.</li>
       <li>Let <var>client</var> be the <a href="#dfn-service-worker-client">service worker client</a> that corresponds to <var>request</var>'s <a for="request">client</a>.</li>
-      <li>Let <var>navigationPreload</var> be null.</li>
+      <li>Let <var>preloadResponse</var> be a new <a>promise</a>.</li>
       <li>Assert: <var>request</var>'s <a for="request">destination</a> is not "<code>serviceworker</code>".</li>
       <li>If <var>request</var> is a <a>potential-navigation-or-subresource request</a>, then:
         <ol>
@@ -3739,22 +3747,22 @@ spec: webidl; urlPrefix: https://heycam.github.io/webidl/
               <li>Let <var>preloadResponseObject</var> be a new {{Response}} object and a new associated {{Headers}} object whose <a>guard</a> is "<code>immutable</code>"</li>
               <li><a>Append to header list</a> <var>preloadRequestHeaders</var> a new <a>header</a> whose <a>name</a> is `<code>Service-Worker-Navigation-Preload</code>` and <a>value</a> is <var>registration</var>'s <a>navigation preload header value</a></li>
               <li>Set <var>preloadRequest</var>'s <a>skip-service-worker flag</a></li>
-              <li>Set <var>navigationPreload</var> to a new <a>promise</a>.</li>
               <li>Run the following substeps <a>in parallel</a>:
                 <ol>
                   <li>
                     <p><a>Fetch</a> <var>preloadRequest</var>.</p>
-                    <p>To <a>process response</a> for <var>preloadResponse</var>, run these substeps:</p>
+                    <p>To <a>process response</a> for <var>navigationPreloadResponse</var>, run these substeps:</p>
                     <ol>
-                      <li><p>If <var>preloadResponse</var>'s <a for="response">type</a> is "<code>error</code>", reject <var>navigationPreload</var> with a <code>TypeError</code> and terminate these substeps.</li>
-                      <li><p>Associate <var>preloadResponseObject</var> with <var>preloadResponse</var>.
-                      <li><p>Resolve <var>navigationPreload</var> with <var>preloadResponseObject</var>.
-                      </ol>
+                      <li>If <var>navigationPreloadResponse</var>'s <a for="response">type</a> is "<code>error</code>", reject <var>navigationPreload</var> with a <code>TypeError</code> and terminate these substeps.</li>
+                      <li>Associate <var>preloadResponseObject</var> with <var>navigationPreloadResponse</var>.
+                      <li>Resolve <var>preloadResponse</var> with <var>navigationPreloadResponse</var>.
+                    </ol>
                   </li>
                 </ol>
               </li>
             </ol>
           </li>
+          <li>Else, resolve <var>preloadResponse</var> with undefined.</li>
         </ol>
         <p class="note">From this point, the <a href="#dfn-service-worker-client">service worker client</a> starts to <a href="#dfn-use">use</a> its <a href="#dfn-service-worker-client-active-worker">active worker</a>'s <a href="#dfn-containing-service-worker-registration">containing service worker registration</a>.</p>
       </li>
@@ -3774,6 +3782,7 @@ spec: webidl; urlPrefix: https://heycam.github.io/webidl/
         <ol>
           <li>Create a <a>trusted event</a> <var>e</var> that uses the {{FetchEvent}} interface, with the event type <code><a href="#service-worker-global-scope-fetch-event">fetch</a></code>, which does not bubble.</li>
           <li>Let the <a href="#fetch-event-request-attribute">request</a> attribute of <var>e</var> be initialized to <var>r</var>.</li>
+          <li>Let the <a href="#fetch-event-preloadresponse-attribute">preloadResponse</a> attribute of <var>e</var> be initialized to <var>preloadResponse</var>.</li>
           <li>Let the <a href="#fetch-event-clientid-attribute">clientId</a> attribute of <var>e</var> be initialized to <var>client</var>'s <a href="#dfn-service-worker-client-id">id</a> if <var>request</var> is not a <a>non-subresource request</a>, and to null otherwise.</li>
           <li>Let the <a href="#fetch-event-isreload-attribute">isReload</a> attribute of <var>e</var> be initialized to <code>true</code> if <var>request</var>'s <a for="request">client</a> is a <a href="#dfn-window-client">window client</a> and the event was dispatched with the user's intention for the page reload, and <code>false</code> otherwise.</li>
           <li><a>Dispatch</a> <var>e</var> at <var>activeWorker</var>'s <a>environment settings object</a>'s <a for="environment settings object">global object</a>.</li>