Specify browser UI-initiated navigations better

In particular, they have a null sourceDocument. We need to handle that in various places in the specification.

Also incorporate the latest changes to Fetch (whatwg/fetch@41185ac) and set the "traversable for user prompts" correctly.

Closes whatwg#9133.

Author: domenic

source

@@ -2705,6 +2705,8 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
        <li><dfn data-x="concept-request-user-activation" data-x-href="https://fetch.spec.whatwg.org/#request-user-activation">user-activation</dfn></li>
        <li><dfn data-x="concept-request-render-blocking" data-x-href="https://fetch.spec.whatwg.org/#request-render-blocking">render-blocking</dfn></li>
        <li><dfn data-x="concept-request-initiator-type" data-x-href="https://fetch.spec.whatwg.org/#request-initiator-type">initiator type</dfn></li>
+       <li><dfn data-x="concept-request-service-workers-mode" data-x-href="https://fetch.spec.whatwg.org/#request-service-workers-mode">service-workers mode</dfn></li>
+       <li><dfn data-x="concept-request-traversable-for-user-prompts" data-x-href="https://fetch.spec.whatwg.org/#concept-request-window">traversable for user prompts</dfn></li>
        <li><dfn data-x-href="https://fetch.spec.whatwg.org/#concept-request-add-range-header">add a range header</dfn></li>
       </ul>
      </li>
@@ -100895,36 +100897,66 @@ location.href = '#foo';</code></pre>
    <dd>a boolean</dd>
 
    <dt><dfn data-x="source-snapshot-params-client">fetch client</dfn></dt>
-   <dd>an <span>environment settings object</span>, only to be used as a <span
+   <dd>an <span>environment settings object</span> or null, only to be used as a <span
    data-x="concept-request-client">request client</span></dd>
 
    <dt><dfn data-x="source-snapshot-params-policy-container">source policy container</dfn></dt>
    <dd>a <span>policy container</span></dd>
   </dl>
 
   <p>To <dfn data-x="snapshotting source snapshot params">snapshot source snapshot params</dfn>
-  given a <code>Document</code> <var>sourceDocument</var>, return a new <span>source snapshot
-  params</span> with</p>
+  given a <code>Document</code>-or-null <var>sourceDocument</var>:</p>
 
-  <dl class="props">
-   <dt><span data-x="source-snapshot-params-activation">has transient activation</span></dt>
-   <dd>true if <var>sourceDocument</var>'s <span>relevant global object</span> has <span>transient
-   activation</span>; otherwise false</dd>
+  <ol>
+   <li>
+    <p>If <var>sourceDocument</var> is null, then return a new <span>source snapshot params</span>
+    with</p>
+
+    <dl class="props">
+     <dt><span data-x="source-snapshot-params-activation">has transient activation</span></dt>
+     <dd>true</dd>
 
-   <dt><span data-x="source-snapshot-params-sandbox">sandboxing flags</span></dt>
-   <dd><var>sourceDocument</var>'s <span>active sandboxing flag set</span></dd>
+     <dt><span data-x="source-snapshot-params-sandbox">sandboxing flags</span></dt>
+     <dd>an empty <span>sandboxing flag set</span></dd>
 
-   <dt><span data-x="source-snapshot-params-download">allows downloading</span></dt>
-   <dd>false if <var>sourceDocument</var>'s <span>active sandboxing flag set</span> has the
-   <span>sandboxed downloads browsing context flag</span> set; otherwise true</dd>
+     <dt><span data-x="source-snapshot-params-download">allows downloading</span></dt>
+     <dd>true</dd>
 
-   <dt><span data-x="source-snapshot-params-client">fetch client</span></dt>
-   <dd><var>sourceDocument</var>'s <span>relevant settings object</span></dd>
+     <dt><span data-x="source-snapshot-params-client">fetch client</span></dt>
+     <dd>null</dd>
 
-   <dt><span data-x="source-snapshot-params-policy-container">source policy container</span></dt>
-   <dd>a <span data-x="clone a policy container">clone</span> of <var>sourceDocument</var>'s <span
-   data-x="concept-document-policy-container">policy container</span></dd>
-  </dl>
+     <dt><span data-x="source-snapshot-params-policy-container">source policy container</span></dt>
+     <dd>a new <span>policy container</span></dd>
+    </dl>
+
+    <p class="note">This <a href="#assert-null-sourcedocument">only occurs</a> in the case of a
+    browser UI-initiated navigation.</p>
+   </li>
+
+   <li>
+    <p>Return a new <span>source snapshot params</span> with
+
+    <dl class="props">
+     <dt><span data-x="source-snapshot-params-activation">has transient activation</span></dt>
+     <dd>true if <var>sourceDocument</var>'s <span>relevant global object</span> has <span>transient
+     activation</span>; otherwise false</dd>
+
+     <dt><span data-x="source-snapshot-params-sandbox">sandboxing flags</span></dt>
+     <dd><var>sourceDocument</var>'s <span>active sandboxing flag set</span></dd>
+
+     <dt><span data-x="source-snapshot-params-download">allows downloading</span></dt>
+     <dd>false if <var>sourceDocument</var>'s <span>active sandboxing flag set</span> has the
+     <span>sandboxed downloads browsing context flag</span> set; otherwise true</dd>
+
+     <dt><span data-x="source-snapshot-params-client">fetch client</span></dt>
+     <dd><var>sourceDocument</var>'s <span>relevant settings object</span></dd>
+
+     <dt><span data-x="source-snapshot-params-policy-container">source policy container</span></dt>
+     <dd>a <span data-x="clone a policy container">clone</span> of <var>sourceDocument</var>'s <span
+     data-x="concept-document-policy-container">policy container</span></dd>
+    </dl>
+   </li>
+  </ol>
 
   <hr>
 
@@ -101127,22 +101159,22 @@ location.href = '#foo';</code></pre>
   it, search for "DONAV" -->
 
   <p>To <dfn export>navigate</dfn> a <span>navigable</span> <var>navigable</var> to a
-  <span>URL</span> <var>url</var> using a <code>Document</code> <var
-  id="source-browsing-context">sourceDocument</var>, with an optional <span>POST resource</span>,
-  string, or null <dfn for="navigate" data-x="navigation-resource"
+  <span>URL</span> <var>url</var> using an optional <code>Document</code>-or-null <var
+  id="source-browsing-context">sourceDocument</var> (default null), with an optional <span>POST
+  resource</span>, string, or null <dfn for="navigate" data-x="navigation-resource"
   export><var>documentResource</var></dfn> (default null), an optional <span
-  data-x="concept-response">response</span>-or-null <dfn for="navigate"
-  data-x="navigation-response" export><var>response</var></dfn> (default null), an optional boolean
-  <dfn for="navigate" id="exceptions-enabled" export><var>exceptionsEnabled</var></dfn> (default
-  false), an optional <code>NavigationHistoryBehavior</code> <dfn for="navigate"
-  data-x="navigation-hh" export><var>historyHandling</var></dfn> (default "<code
+  data-x="concept-response">response</span>-or-null <dfn for="navigate" data-x="navigation-response"
+  export><var>response</var></dfn> (default null), an optional boolean <dfn for="navigate"
+  id="exceptions-enabled" export><var>exceptionsEnabled</var></dfn> (default false), an optional
+  <code>NavigationHistoryBehavior</code> <dfn for="navigate" data-x="navigation-hh"
+  export><var>historyHandling</var></dfn> (default "<code
   data-x="NavigationHistoryBehavior-auto">auto</code>"), an optional <span>serialized
   state</span>-or-null <dfn for="navigate" data-x="navigation-navigation-api-state"
   export><var>navigationAPIState</var></dfn> (default null), an optional <span>entry list</span> or
   null <dfn for="navigate" data-x="navigation-form-data-entry-list"
-  export><var>formDataEntryList</var></dfn> (default null), an optional <span>referrer
-  policy</span> <dfn data-x="navigation-referrer-policy"><var>referrerPolicy</var></dfn> (default
-  the empty string), an optional <span>user navigation involvement</span> <dfn
+  export><var>formDataEntryList</var></dfn> (default null), an optional <span>referrer policy</span>
+  <dfn data-x="navigation-referrer-policy"><var>referrerPolicy</var></dfn> (default the empty
+  string), an optional <span>user navigation involvement</span> <dfn
   data-x="navigation-user-involvement"><var>userInvolvement</var></dfn> (default "<code
   data-x="uni-none">none</code>"), an optional <code>Element</code> <dfn
   data-x="navigation-source-element"><var>sourceElement</var></dfn> (default null), and an
@@ -101157,22 +101189,49 @@ location.href = '#foo';</code></pre>
    <li><p>Let <var>sourceSnapshotParams</var> be the result of <span>snapshotting source snapshot
    params</span> given <var>sourceDocument</var>.</p></li>
 
-   <li><p>Let <var>initiatorOriginSnapshot</var> be <var>sourceDocument</var>'s <span
-   data-x="concept-document-origin">origin</span>.</p></li>
+   <li><p>Let <var>initiatorOriginSnapshot</var> be a new <span
+   data-x="concept-origin-opaque">opaque origin</span>.</p></li>
 
-   <li><p>Let <var>initiatorBaseURLSnapshot</var> be <var>sourceDocument</var>'s <span>document base
-   URL</span>.</p></li>
+   <li><p>Let <var>initiatorBaseURLSnapshot</var> be <code>about:blank</code>.</p></li>
 
-   <li id="sandboxLinks">
-    <p>If <var>sourceDocument</var>'s <span>node navigable</span> is not <span>allowed by
-    sandboxing to navigate</span> <var>navigable</var> given <var>sourceSnapshotParams</var>,
-    then:</p>
+   <li>
+    <p>If <var>sourceDocument</var> is null:</p>
 
     <ol>
-     <li><p>If <var>exceptionsEnabled</var> is true, then throw a
-     <span>"<code>SecurityError</code>"</span> <code>DOMException</code>.</p></li>
+     <li id="assert-null-sourcedocument"><p><span>Assert</span>: <var>userInvolvement</var> is
+     "<code data-x="uni-browser-ui">browser UI</code>".</p></li>
 
-     <li><p>Return.</p></li>
+     <li><p>If <var>url</var>'s <span data-x="concept-url-scheme">scheme</span> is "<code
+     data-x="javascript protocol">javascript</code>", then set <var>initiatorOriginSnapshot</var> to
+     <var>navigable</var>'s <span data-x="nav-document">active document</span>'s <span
+     data-x="concept-document-origin">origin</span>.</p></li>
+    </ol>
+   </li>
+
+   <li>
+    <p>Otherwise:</p>
+
+    <ol>
+     <li><p><span>Assert</span>: <var>userInvolvement</var> is not "<code
+     data-x="uni-browser-ui">browser UI</code>".</p></li>
+
+     <li id="sandboxLinks">
+      <p>If <var>sourceDocument</var>'s <span>node navigable</span> is not <span>allowed by
+      sandboxing to navigate</span> <var>navigable</var> given <var>sourceSnapshotParams</var>:</p>
+
+      <ol>
+       <li><p>If <var>exceptionsEnabled</var> is true, then throw a
+       <span>"<code>SecurityError</code>"</span> <code>DOMException</code>.</p></li>
+
+       <li><p>Return.</p></li>
+      </ol>
+     </li>
+
+     <li><p>Set <var>initiatorOriginSnapshot</var> to <var>sourceDocument</var>'s <span
+     data-x="concept-document-origin">origin</span>.</p></li>
+
+     <li><p>Set <var>initiatorBaseURLSnapshot</var> to <var>sourceDocument</var>'s <span>document
+     base URL</span>.</p></li>
     </ol>
    </li>
 
@@ -101467,14 +101526,17 @@ location.href = '#foo';</code></pre>
       responses</span> after the initial response.</p>
 
       <ol>
+       <li><p>Let <var>sourcePolicyContainer</var> be a <span data-x="clone a policy
+       container">clone</span> of the <var>sourceDocument</var>'s <span
+       data-x="concept-document-policy-container">policy container</span>, if
+       <var>sourceDocument</var> is not null; otherwise null.</p></li>
+
        <li><p>Let <var>policyContainer</var> be the result of <span data-x="determining navigation
        params policy container">determining navigation params policy container</span> given <span
        data-x="concept-response">response</span>'s <span data-x="concept-response-url">URL</span>,
-       null, a <span data-x="clone a policy container">clone</span> of the
-       <var>sourceDocument</var>'s <span data-x="concept-document-policy-container">policy
-       container</span>, <var>navigable</var>'s <span data-x="nav-container-document">container
-       document</span>'s <span data-x="concept-document-policy-container">policy container</span>,
-       and null.</p></li>
+       null, <var>sourcePolicyContainer</var>, <var>navigable</var>'s <span
+       data-x="nav-container-document">container document</span>'s <span
+       data-x="concept-document-policy-container">policy container</span>, and null.</p></li>
 
        <li><p>Let <var>finalSandboxFlags</var> be the <span data-x="set union">union</span> of
        <var>targetSnapshotParams</var>'s <span data-x="target-snapshot-params-sandbox">sandboxing
@@ -103408,11 +103470,33 @@ location.href = '#foo';</code></pre>
      <dt><span data-x="concept-request-policy-container">policy container</span></dt>
      <dd><var>sourceSnapshotParams</var>'s <span
      data-x="source-snapshot-params-policy-container">source policy container</span></dd>
+
+     <dt><span data-x="concept-request-traversable-for-user-prompts">traversable for user prompts</span></dt>
+     <dd><var>navigable</var>'s <span data-x="nav-top">top-level traversable</span></dd>
     </dl>
    </li>
 
    <li>
-    <p>If <var>documentResource</var> is a <span>POST resource</span>, then:</p>
+    <p>If <var>request</var>'s <span data-x="concept-request-client">client</span> is null:</p>
+
+    <p class="note">This <a href="#assert-null-sourcedocument">only occurs</a> in the case of a
+    browser UI-initiated navigation.</p>
+
+    <ol>
+     <li><p>Set <var>request</var>'s <span data-x="concept-request-origin">origin</span> to a new
+     <span data-x="concept-origin-opaque">opaque origin</span>.</p></li>
+
+     <li><p>Set <var>request</var>'s <span
+     data-x="concept-request-service-workers-mode">service-workers mode</span> to "<code
+     data-x="">all</code>".</p></li>
+
+     <li><p>Set <var>request</var>'s <span data-x="concept-request-referrer">referrer</span> to
+     "<code data-x="">no-referrer</code>".</p></li>
+    </ol>
+   </li>
+
+   <li>
+    <p>If <var>documentResource</var> is a <span>POST resource</span>:</p>
 
     <ol>
      <li><p>Set <var>request</var>'s <span data-x="concept-request-method">method</span> to `<code