Remove overridden reload concept

Or: document.open() simplifications, part 1.9.

This behavior is only implemented in Firefox and Edge and has
contributed to developer confusion. See
https://bugzilla.mozilla.org/show_bug.cgi?id=556002.

This is a part of the effort to renovate document.open(). See
#3818 for context.

Tests: web-platform-tests/wpt#12555

source

@@ -9133,60 +9133,6 @@ o.myself = o;</code></pre>
   that can be set when the <code>Document</code> is created. If it is not explicitly set, then its
   value is the empty string.</p>
 
-  <p>Each <code>Document</code> object has a <dfn>reload override flag</dfn> that is originally
-  unset. The flag is set by the <code data-x="dom-document-open">document.open(<var>type</var>,
-  <var>replace</var>)</code> and <code data-x="dom-document-write">document.write()</code> methods
-  in certain situations. When the flag is set, the <code>Document</code> also has a <dfn>reload
-  override buffer</dfn> which is a Unicode string that is used as the source of the document when it
-  is reloaded.</p>
-
-  <p>When the user agent is to perform <dfn>an overridden reload</dfn>, given a <span>source
-  browsing context</span>, it must act as follows:</p>
-
-  <ol>
-
-   <li><p>Let <var>source</var> be the value of the <span>browsing context</span>'s
-   <span>active document</span>'s <span>reload override buffer</span>.</p></li>
-
-   <li><p>Let <var>address</var> be the <span>browsing context</span>'s <span>active
-   document</span>'s <span data-x="concept-document-url">URL</span>.</p></li>
-
-   <li><p>Let <var>HTTPS state</var> be the <span data-x="concept-document-https-state">HTTPS
-   state</span> of the <span>browsing context</span>'s <span>active document</span>.</p></li>
-
-   <li><p>Let <var>referrer policy</var> be the <span
-   data-x="concept-document-referrer-policy">referrer policy</span> of the <span>browsing
-   context</span>'s <span>active document</span>.</p></li>
-
-   <li><p>Let <var>CSP list</var> be the <span data-x="concept-document-csp-list">CSP list</span>
-   of the <span>browsing context</span>'s <span>active document</span>.</p></li>
-
-   <li>
-
-    <p><span>Navigate</span><!--DONAV reload after d.open()--> the <span>browsing context</span> to
-    a new <span data-x="concept-response">response</span> whose <span
-    data-x="concept-response-body">body</span> is <var>source</var>, <span
-    data-x="concept-response-header-list">header list</span> is `<code
-    data-x="http-referrer-policy">Referrer-Policy</code>`/<var>referrer policy</var>, <span
-    data-x="concept-response-csp-list">CSP list</span> is <var>CSP list</var> and <span
-    data-x="concept-response-https-state">HTTPS state</span> is <var>HTTPS state</var>, with the
-    <var><span>exceptions enabled flag</span></var> set and <span>replacement enabled</span>. The
-    <span>source browsing context</span> is that given to the <span data-x="an overridden
-    reload">overridden reload</span> algorithm. When the <span>navigate</span> algorithm creates a
-    <code>Document</code> object for this purpose, set that <code>Document</code>'s <span>reload
-    override flag</span> and set its <span>reload override buffer</span> to <var>source</var>.
-    Rethrow any exceptions.</p>
-
-    <p>When it comes time to <span>set the document's address</span> in the <span
-    data-x="navigate">navigation algorithm</span>, use <var>address</var> as the
-    <span>override URL</span>.</p>
-
-   </li>
-
-
-  </ol>
-
-
 
   <h4>The <code>Document</code> object</h4>
 
@@ -81613,13 +81559,6 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
    attributes</span> of the <span>browsing context</span>'s <span>browsing context
    container</span>.</p></dd>
 
-   <dt>If the <span>browsing context</span>'s <span>active document</span> has its <span>reload
-   override flag</span> set</dt>
-
-   <dd><p>Perform <span>an overridden reload</span>, with the <span>browsing context</span> being
-   navigated as the <span>responsible browsing context</span>. Rethrow any exceptions.</p></dd>
-   <!-- https://damowmow.com/playground/demos/sandbox/001.html -->
-
    <dt>Otherwise</dt>
 
    <dd><p><span>Navigate</span><!--DONAV location.reload()--> the <span>browsing context</span> to
@@ -81646,10 +81585,7 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
   In the case of non-idempotent methods (e.g. HTTP POST), the user agent should prompt the user to
   confirm the operation first, since otherwise transactions (e.g. purchases or database
   modifications) could be repeated. User agents may allow the user to explicitly override any caches
-  when reloading. If <span>browsing context</span>'s <span>active document</span>'s <span>reload
-  override flag</span> is set, then the user agent may instead perform <span>an overridden
-  reload</span> rather than the navigation described in this paragraph (with the <span>browsing
-  context</span> being reloaded as the <span>source browsing context</span>).</p>
+  when reloading.</p>
 
   <hr>
 
@@ -82039,9 +81975,6 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
         the bytes that comprise a <span data-x="concept-response-body">response body</span> is
         not yet specified, pending further investigation into user agent behavior. See <a
         href="https://github.com/whatwg/html/issues/1129">issue #1129</a>.</p>
-
-        <p>When it comes time to <span>set the document's address</span>, use <var>address</var> as
-        the <span>override URL</span>.</p>
        </li>
 
        <li><p>Run <span>process a navigate response</span> with <var>resource</var>,
@@ -82380,17 +82313,10 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
     application), or one for which the user agent has dedicated processing rules, or one for which
     the user agent has a dedicated handler.</p>
 
-    <p><dfn data-x="set the document's address">Setting the document's address</dfn>: If there is no
-    <dfn>override URL</dfn>, then any <code>Document</code> created by these steps must have its
-    <span data-x="concept-document-url">URL</span> set to the <span>URL</span> that was
-    originally to be fetched, ignoring any other data that was used to obtain the resource. However,
-    if there <em>is</em> an <span>override URL</span>, then any <code>Document</code> created by
-    these steps must have its <span data-x="concept-document-url">URL</span> set to that
-    <span>URL</span> instead.</p>
-
-    <p class="note">An <span data-x="override URL">override URL</span> is set when <span
-    data-x="javascript protocol">dereferencing a <code>javascript:</code> URL</span> and when
-    performing <span>an overridden reload</span>.</p>
+    <p><dfn data-x="set the document's address">Setting the document's address</dfn>: Any
+    <code>Document</code> created by these steps must have its <span
+    data-x="concept-document-url">URL</span> set to the <span>URL</span> that was originally to be
+    fetched, ignoring any other data that was used to obtain the resource.</p>
 
     <p><!--en-GB--><dfn id="initialise-the-document-object" data-x="initialize the Document object"
     data-export="">Initializing a new <code>Document</code> object</dfn>: when a
@@ -91038,10 +90964,6 @@ document.body.appendChild(frame)</code></pre>
    <li><p><span data-x="concept-node-replace-all">Replace all</span> with null within
    <var>document</var>, without firing any mutation events.</p></li>
 
-   <li><p>If <var>document</var> is <span>ready for post-load tasks</span>, then set
-   <var>document</var>'s <span>reload override flag</span> and set <var>document</var>'s
-   <span>reload override buffer</span> to the empty string.</p></li>
-
    <li><p>Change <var>document</var>'s <span data-x="concept-document-url">URL</span> to the
    <span data-x="concept-document-url">URL</span> of the <span>responsible document</span> specified
    by the <span>entry settings object</span>.</p></li>
@@ -91254,9 +91176,6 @@ document.body.appendChild(frame)</code></pre>
    <li><p>Insert <var>input</var> into the <span>input stream</span> just before the <span>insertion
    point</span>.</p></li>
 
-   <li><p>If <var>document</var>'s <span>reload override flag</span> is set, then append
-   <var>input</var> to <var>document</var>'s <span>reload override buffer</span>.</p></li>
-
    <li>
     <p>If there is no <span>pending parsing-blocking script</span>, have the <span>HTML
     parser</span> process <var>input</var>, one code point at a time, processing resulting tokens as