Create timing info for HTTP(S) network errors

Tests: web-platform-tests/wpt#30968.

Closes whatwg#1215.

fetch.bs

@@ -4210,11 +4210,68 @@ steps:
 <a for=/>response</a> <var>response</var>, run these steps:
 
 <ol>
+ <li>
+  <p>If <var>response</var> is a <a>network error</a>, then:
+
+  <ol>
+   <li>
+    <p>Set <var>response</var>'s <a for=response>URL list</a> to « <var>fetchParams</var>'s
+    <a for="fetch params">request</a>'s <a for=request>URL list</a>[0] ».
+
+    <p class=note>This is needed as after <a for=list>cloning</a> <var>fetchParams</var>'s
+    <a for="fetch params">request</a>'s <a for=request>URL list</a> earlier, <var>response</var>
+    might have been set to a <a>network error</a>.</p>
+   </li>
+
+   <li><p>Set <var>response</var>'s <a for=response>timing info</a> to the result of
+   <a>creating an opaque timing info</a> for <var>fetchParams</var>'s
+   <a for="fetch params">timing info</a>.</p></li>
+  </ol>
+ </li>
+
+ <li>
+  <p>Let <var>processResponseDone</var> be the following steps:
+
+  <ol>
+   <li><p>Set <var>fetchParams</var>'s <a for="fetch params">request</a>'s
+   <a for=request>done flag</a>.
+
+   <li><p>If <var>fetchParams</var>'s <a for="fetch params">process response done</a> is not null,
+   then <a>queue a fetch task</a> to run <var>fetchParams</var>'s
+   <a for="fetch params">process response done</a> given <var>response</var> with
+   <var>fetchParams</var>'s <a for="fetch params">task destination</a>.
+  </ol>
+ </li>
+
  <li><p>If <var>fetchParams</var>'s <a for="fetch params">process response</a> is non-null, then
  <a>queue a fetch task</a> to run <var>fetchParams</var>'s
  <a for="fetch params">process response</a> given <var>response</var>, with <var>fetchParams</var>'s
  <a for="fetch params">task destination</a>.
 
+ <li><p>If <var>response</var>'s <a for=response>body</a> is null, then run
+ <var>processResponseDone</var>.
+
+ <li>
+  <p>Otherwise:</p>
+
+  <ol>
+   <li><p>Let <var>transformStream</var> be a new a {{TransformStream}}.
+
+   <li><p>Let <var>identityTransformAlgorithm</var> be an algorithm which, given <var>chunk</var>,
+   <a for=TransformStream lt=enqueue>enqueues</a> <var>chunk</var> in <var>transformStream</var>.
+
+   <li><p><a for=TransformStream lt="setting up">Set up</a> <var>transformStream</var> with
+   <a for="TransformStream/set up"><i>transformAlgorithm</i></a> set to <var>identityTransformAlgorithm</var> and
+   <a for="TransformStream/set up"><i>flushAlgorithm</i></a> set to <var>processResponseDone</var>.
+
+   <li><p>Set <var>response</var>'s <a for=response>body</a> to the result of
+   <a for=ReadableStream lt="piping through">piping</a> <var>response</var>'s
+   <a for=response>body</a> through <var>transformStream</var>.
+  </ol>
+
+  <p class=note>This {{TransformStream}} is needed for the purpose of receiving a notification when
+  the stream reaches its end, and is otherwise an <a>identity transform stream</a>.
+
  <li>
   <p>If <var>fetchParams</var>'s <a for="fetch params">process response end-of-body</a> is non-null,
   then:
@@ -4237,24 +4294,13 @@ steps:
   </ol>
 </ol>
 
-<p>To <dfn>finalize response</dfn> given a <a for=/>fetch params</a> <var>fetchParams</var> and a
-<a for=/>response</a> <var>response</var>, run these steps:
-
-<ol>
- <li><p>Set <var>fetchParams</var>'s <a for="fetch params">request</a>'s
- <a for=request>done flag</a>.
-
- <li><p>If <var>fetchParams</var>'s <a for="fetch params">process response done</a> is not null,
- then <a>queue a fetch task</a> to run <var>fetchParams</var>'s
- <a for="fetch params">process response done</a> given <var>response</var>,
- with <var>fetchParams</var>'s <a for="fetch params">task destination</a>.
-</ol>
-
 <p>To <dfn export>finalize and report timing</dfn> given a <a for=/>response</a>
 <var>response</var>, a <a for=/>global object</a> <var>global</var>, and a <a for=/>string</a>
 <var>initiatorType</var> (default "<code>other</code>"), run these steps:
 
 <ol>
+ <li><p>If <var>response</var> is an <a>aborted network error</a>, then return.
+
  <li><p>If <var>response</var>'s <a for=response>URL list</a> is null or
  <a for=list lt="is empty">empty</a>, then return.
 
@@ -4264,6 +4310,9 @@ steps:
 
  <li><p>Let <var>cacheState</var> be <var>response</var>'s <a for=response>cache state</a>.
 
+ <li><p>If <var>originalURL</var>'s <a for=url>scheme</a> is not an <a>HTTP(S) scheme</a>, then
+ return.
+
  <li><p>If <var>timingInfo</var> is null, then return.
 
  <li>
@@ -5596,17 +5645,14 @@ optional boolean <var>forceNewConnection</var> (default false), run these steps:
 
        <li><p>Otherwise, if the bytes transmission for <var>response</var>'s message body is done
        normally and <var>stream</var> is <a for=ReadableStream>readable</a>, then
-       <a for=ReadableStream>close</a> <var>stream</var>, <a for=/>finalize response</a> for
-       <var>fetchParams</var> and <var>response</var>, and abort these in-parallel steps.
+       <a for=ReadableStream>close</a> <var>stream</var>, and abort these in-parallel steps.
       </ol>
     </ol>
 
    <li>
     <p><a>If aborted</a>, then:
 
     <ol>
-     <li><a for=/>Finalize response</a> for <var>fetchParams</var> and <var>response</var>.
-
      <li><p>Let <var>aborted</var> be the termination's aborted flag.
 
      <li>