Align with changes to Service Worker's handle fetch

Update the HTTP fetch algorithm, particularly the handling of the response to Service Worker's handle fetch. Currently, handle fetch is assumed to return null or a response. However, handle fetch can now return service worker timing info when the Service Worker static routing API is used, so that the corresponding timing information are correctly exposed when the ServiceWorker could not handle the fetch (i.e., would previously return null). To support this new return type, we need to update the handling of the response of handle fetch.

To expose the Service Worker timing Info to the resource timing API, we also associate them to the fetch timing info.

Co-authored-by: Anne van Kesteren <annevk@annevk.nl>

Author: quasi-mod

fetch.bs

@@ -367,6 +367,9 @@ following <a for=struct>items</a>: [[RESOURCE-TIMING]] [[NAVIGATION-TIMING]]
  <dt><dfn export for="fetch timing info">final connection timing info</dfn> (default null)
  <dd>Null or a <a for=/>connection timing info</a>.
 
+ <dt><dfn export for="fetch timing info">service worker timing info</dfn> (default null)
+ <dd>Null or a <a for=/>service worker timing info</a>.
+
  <dt><dfn export for="fetch timing info">server-timing headers</dfn> (default « »)
  <dd>A <a for=/>list</a> of strings.
  <dt><dfn export for="fetch timing info">render-blocking</dfn> (default false)
@@ -5602,20 +5605,26 @@ these steps:
    <li><p>Let <var>serviceWorkerStartTime</var> be the <a for=/>coarsened shared current time</a>
    given <var>fetchParams</var>'s <a for="fetch params">cross-origin isolated capability</a>.
 
-   <li><p>Set <var>response</var> to the result of invoking <a for=/>handle fetch</a> for
+   <li><p>Let <var>fetchResponse</var> be the result of invoking <a for=/>handle fetch</a> for
    <var>requestForServiceWorker</var>, with <var>fetchParams</var>'s
    <a for="fetch params">controller</a> and <var>fetchParams</var>'s
    <a for="fetch params">cross-origin isolated capability</a>. [[!HTML]] [[!SW]]
 
    <li>
-    <p>If <var>response</var> is non-null, then:
+    <p>If <var>fetchResponse</var> is a <a for=/>response</a>:
 
     <ol>
+     <li><p>Set <var>response</var> to <var>fetchResponse</var>.
+
      <li><p>Set <var>fetchParams</var>'s <a for="fetch params">timing info</a>'s
      <a for="fetch timing info">final service worker start time</a> to
      <var>serviceWorkerStartTime</var>.
 
-     <li>If <var>request</var>'s <a for=request>body</a> is non-null, then
+     <li><p>Set <var>fetchParams</var>'s <a for="fetch params">timing info</a>'s
+     <a for="fetch timing info">service worker timing info</a> to <var>response</var>'s
+     <a for="response">service worker timing info</a>.
+
+     <li><p>If <var>request</var>'s <a for=request>body</a> is non-null, then
      <a for=ReadableStream>cancel</a> <var>request</var>'s <a for=request>body</a> with undefined.
 
      <li><p>Set <var>internalResponse</var> to <var>response</var>, if <var>response</var> is not a
@@ -5638,11 +5647,15 @@ these steps:
        <var>response</var>'s <a for=response>type</a> is "<code>opaqueredirect</code>"
 
        <li><var>request</var>'s <a for=request>redirect mode</a> is not "<code>follow</code>" and
-       <var>response</var>'s <a for=response>URL list</a> has more than one item.
+       <var>response</var>'s <a for=response>URL list</a> has more than one item
       </ul>
 
       <p>then return a <a>network error</a>.
     </ol>
+
+   <li><p>Otherwise, if <var>fetchResponse</var> is a <a for=/>service worker timing info</a>,
+   then set <var>fetchParams</var>'s <a for="fetch params">timing info</a>'s
+   <a for="fetch timing info">service worker timing info</a> to <var>fetchResponse</var>.
   </ol>
 
  <li>
@@ -10182,6 +10195,7 @@ Julian Reschke,
 Jussi Kalliokoski,
 Jxck,
 Kagami Sascha Rosylight,
+Keita Suzuki,
 Keith Yeung,
 Kenji Baheux,
 Lachlan Hunt,