Use controller for navigation redirect

Remove the existing "navigate-redirect fetch" algorithm. Instead, the caller uses the controller to perform the next manual redirect.

This simplifies the flow in the HTML Standard flow, as now there is a single "fetch params" struct for the course of the entire navigation. Up until now some data from fetch params would be lost, like timing info and task desination, because navigation fetches create a brand new "fetch params" struct. Now that data is retained, and the only thing that HTML needs to do is call "process the next redirect" on the fetch controller.

Co-authored-by: Domenic Denicola <[email protected]>

Author: noamr

fetch.bs

@@ -238,6 +238,9 @@ lt="authentication entry">authentication entries</a> (for HTTP authentication).
 
  <dt><dfn for="fetch controller">serialized abort reason</dfn> (default null)
  <dd>Null or a <a>Record</a> (result of [$StructuredSerialize$]).
+
+ <dt><dfn for="fetch controller">next manual redirect steps</dfn> (default null)
+ <dd>Null or an algorithm accepting nothing.
 </dl>
 
 <p>To <dfn export for="fetch controller" id="finalize-and-report-timing">report timing</dfn> for a
@@ -250,6 +253,16 @@ lt="authentication entry">authentication entries</a> (for HTTP authentication).
  <li><p>Call <a>this</a>'s <a for="fetch controller">report timing steps</a> with <var>global</var>.
 </ol>
 
+<p>To <dfn export for="fetch controller">process the next manual redirect</dfn> for a
+<a>fetch controller</a> <var>controller</var>:
+
+<ol>
+ <li><p><a for=/>Assert</a>: <var>controller</var>'s
+ <a for="fetch controller">next manual redirect steps</a> are not null.
+
+ <li><p>Call <var>controller</var>'s <a for="fetch controller">next manual redirect steps</a>.
+</ol>
+
 <p>To <dfn export for="fetch controller" id="extract-full-timing-info">extract full timing info</a>
 given a <a>fetch controller</a> <var>controller</var>:
 
@@ -4834,7 +4847,11 @@ these steps:
 
      <dt>"<code>manual</code>"
      <dd><p>Set <var>response</var> to an <a>opaque-redirect filtered response</a> whose
-     <a for="filtered response">internal response</a> is <var>actualResponse</var>.
+     <a for="filtered response">internal response</a> is <var>actualResponse</var>. If
+     <var>request</var>'s <a for=request>mode</a> is "<code>navigate</code>", then set
+     <var>fetchParams</var>'s <a for="fetch params">controller</a>'s <a
+     for="fetch controller">next manual redirect steps</a> to run <a>HTTP-redirect fetch</a> given
+     <var>fetchParams</var> and <var>response</var>.
 
      <dt>"<code>follow</code>"
      <dd><p>Set <var>response</var> to the result of running <a>HTTP-redirect fetch</a> given
@@ -4948,26 +4965,6 @@ run these steps:
 </ol>
 
 
-<h3 id=navigate-redirect-fetch>Navigate-redirect fetch</h3>
-
-<p class=note>This algorithm is used by <cite>HTML</cite>'s navigate algorithm. It is expected to be
-invoked while <a>in parallel</a>. [[!HTML]]
-
-<p>To <dfn export id=concept-navigate-redirect-fetch>navigate-redirect fetch</dfn>, given a
-<a for=/>request</a> <var>request</var> and <a for=/>response</a> <var>response</var>, run these
-steps. They return a <a for=/>response</a>.
-
-<ol>
- <li><p>Assert: <var>request</var>'s <a for=request>redirect mode</a> is "<code>manual</code>".
-
- <li><p>Let <var>fetchParams</var> be a new <a for=/>fetch params</a> whose
- <a for="fetch params">request</a> is <var>request</var>.
-
- <li><p>Return the result of running <a>HTTP-redirect fetch</a> given <var>fetchParams</var> and
- <var>response</var>.
-</ol>
-
-
 <h3 id=http-network-or-cache-fetch>HTTP-network-or-cache fetch</h3>
 
 <p>To <dfn id=concept-http-network-or-cache-fetch>HTTP-network-or-cache fetch</dfn>, given a
@@ -8321,10 +8318,19 @@ in a <a for=/>parallel queue</a> if <a for=fetch><i>useParallelQueue</i></a> is
  <cite>HTML</cite>. [[HTML]]
 
  <dt><a for=fetch><i>processResponse</i></a>
- <dd><p>Takes an algorithm that will be passed a <a for=/>response</a>. Indicates
- <a for=/>response</a>'s <a for=response>header list</a> has been received and initialized. This
- is primarily useful for standards that want to operate on <a for=/>response</a>'s
- <a for=response>body</a>'s <a for=body>stream</a> directly.
+ <dd>
+  <p>Takes an algorithm that will be passed a <a for=/>response</a>. Indicates
+  <a for=/>response</a>'s <a for=response>header list</a> has been received and initialized. This
+  is primarily useful for standards that want to operate on <a for=/>response</a>'s
+  <a for=response>body</a>'s <a for=body>stream</a> directly.
+
+  <p>If the <a for=/>request</a>'s <a for=request>mode</a> is "<code>navigate</code>" and its
+  <a for=request>redirect mode</a> is "<code>manual</code>", then callers need to follow a very
+  specific flow with this algorithm to get the intended behavior. They should compute the
+  appropriate <a for=response>location URL</a>, and if it is not null or a failure, then they
+  should call <a for="fetch controller">process the next manual redirect</a>. This will result in
+  <a for=fetch><i>processResponse</i></a> being called again, with the next <a for=/>response</a>
+  in the redirect chain.
 
  <dt><a for=fetch><i>processResponseEndOfBody</i></a>
  <dd><p>Takes an algorithm that will be passed a <a for=/>response</a>. Indicates the network is