Attach timing info and URL to network errors

Set an opaque timing info and the original request URL to the error
resposne, and call the processResponseDone callback to allow the caller
to report it. This should already be the case for reporting network
errors in the fetch() API.

Closes #1215

Set network error timing info and URL at the start of fetch finale

Rearrange fetch finale step

Make sure we don't report network errors twice

Use queues for synchronization

fetch.bs

@@ -203,6 +203,8 @@ lt="authentication entry">authentication entries</a> (for HTTP authentication).
  <dd>Null, a <a for=/>global object</a>, or a <a for=/>parallel queue</a>.
 
  <dt><dfn for="fetch params">cross-origin isolated capability</dfn> (default false)
+ <dt><dfn for="fetch params">ready for clients</dfn> (default false).
+ <dt><dfn for="fetch params">network read complete</dfn> (default false).
  <dd>A boolean.
 
  <dt><dfn for="fetch params">timing info</dfn>
@@ -4200,6 +4202,27 @@ 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> ≫.
+
+    <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>
+
+   <li><p>Set <var>fetchParams</var>'s <a for="fetch params">network read complete</a> to true.
+  </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
@@ -4225,19 +4248,43 @@ steps:
    <var>processBody</var>, <var>processBodyError</var>, and <var>fetchParams</var>'s
    <a for="fetch params">task destination</a>.
   </ol>
+ </li>
+
+ <li>
+  <p><a>Queue a fetch task</a> to run the following steps with <var>fetchParams</var>'s
+  <a for="fetch params">task destination</a>:</p>
+
+  <ol>
+   <li><p>Set <var>fetchParams</var>'s <a for="fetch params">ready for clients</a> to true.</p></li>
+
+   <li><p><a>Finalize response</a> given <var>fetchParams</var> and <var>response</var>.</p></li>
+  </ol>
+</ol>
+
+<p>To <dfn>fetch network finale</dfn> given a <a for=/>fetch params</a> <var>fetchParams</var>
+and a <a for=/>response</a> <var>response</var>, <a>queue a fetch task</a>
+with to run the following steps with <var>fetchParams</var>'s
+<a for="fetch params">task destination</a>:</p>
+
+<ol>
+ <li><p>Set <var>fetchParams</var>'s <a for="fetch params">network read complete</a>.</p></li>
+
+ <li><p><a>Finalize response</a> given <var>fetchParams</var> and <var>response</var>.</p></li>
 </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>If<var>fetchParams</var>'s <a for="fetch params">ready for clients</a> is false or
+ <var>fetchParams</var>'s <a for="fetch params">network read complete</a> is false, return.</p></li>
+
  <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>.
+ then run <var>fetchParams</var>'s <a for="fetch params">process response done</a> with
+ <var>response</var>.
 </ol>
 
 <p>To <dfn export>finalize and report timing</dfn> given a <a for=/>response</a>
@@ -5586,7 +5633,7 @@ 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
+       <a for=ReadableStream>close</a> <var>stream</var>, run <a for=/>fetch network finale</a> for
        <var>fetchParams</var> and <var>response</var>, and abort these in-parallel steps.
       </ol>
     </ol>
@@ -5595,7 +5642,7 @@ optional boolean <var>forceNewConnection</var> (default false), run these steps:
     <p><a>If aborted</a>, then:
 
     <ol>
-     <li><a for=/>Finalize response</a> for <var>fetchParams</var> and <var>response</var>.
+     <li>Run <a for=/>fetch network finale</a> for <var>fetchParams</var> and <var>response</var>.
 
      <li><p>Let <var>aborted</var> be the termination's aborted flag.