Expose new algorithms to create a Feature Policy before document is c… (#324)

* Expose new algorithms to create a Feature Policy before document is created.

Adjust algorithms so that the HTML spec will be able to create a feature
policy before the document is created. Instead of creating the document
first and then applying it afterwards. The document based algorithms
will remain until the HTML spec is changed.

Author: dtapuska

index.bs

@@ -887,19 +887,18 @@ partial interface HTMLIFrameElement {
     </ol>
   </section>
   <section>
-    <h3 id="algo-initialize-for-document"><dfn export
-    id="initialize-for-document">Initialize <var>document</var>'s Feature
-    Policy</var></dfn></h3>
-    <p>Given a {{Document}} object (<var>document</var>), this algorithm
-    initialises <var>document</var>'s <a>Feature Policy</a></p>
+    <h3 id="algo-create-for-browsingcontext"><dfn export id="create-for-browsingcontext">Create a
+    Feature Policy for a browsing <var>context</var></dfn></h3>
+    <p>Given a <a>browsing context</a> (<var>browsingContext</var>), and an <a>origin</a>
+    (<var>origin</var>) this algorithm returns a new <a>Feature Policy</a>.</p>
     <ol>
       <li>Let <var>inherited policy</var> be a new ordered map.</li>
       <li>Let <var>declared policy</var> be a new ordered map.</li>
       <li>For each <var>feature</var> supported,
         <ol>
-          <li>Let <var>isInherited</var> be the result of running <a>Define an
-          inherited policy for feature in document</a> on <var>feature</var> and
-          <var>document</var>.
+          <li>Let <var>isInherited</var> be the result of running <a
+          href="#define-inherited-policy">Define an inherited policy for feature in browsing
+          context</a> on <var>feature</var>, <var>origin</var> and <var>browsingContext</var>.
           </li>
           <li>Set <var>inherited policy</var>[<var>feature</var>] to
             <var>isInherited</var>.</li>
@@ -909,58 +908,75 @@ partial interface HTMLIFrameElement {
       policy <var>inherited policy</var> and declared policy <var>declared
       policy</var>.
       </li>
+      <li>Return <var>policy</var>.</li>
+    </ol>
+  </section>
+  <section>
+    <h3 id="algo-initialize-for-document"><dfn export
+    id="initialize-for-document">Initialize <var>document</var>'s Feature
+    Policy</dfn></h3>
+    <p>Given a {{Document}} object (<var>document</var>), this algorithm
+    initialises <var>document</var>'s <a>Feature Policy</a></p>
+    <ol>
+      <li>Let <var>policy</var> be the result of running <a>Create a Feature Policy for a browsing
+      context</a> given <var>document</var>'s <a>browsing context</a>, and <var>document</var>'s
+      <a>origin</a>.</li>
       <li>
         Set <var>document</var>’s <a href="https://html.spec.whatwg.org/multipage/dom.html#concept-document-feature-policy">feature policy</a> to <var>policy</var>.
       </li>
     </ol>
   </section>
   <section>
-    <h3 id="algo-initialize-from-response"><dfn export
-    id="initialize-from-response">Initialize <var>document</var>'s Feature
-    Policy from <var>response</var></dfn></h3>
-    <p>Given a [=response=] (<var>response</var>) and a <a>Document</a>
-    (<var>document</var>), this algorithm populates <var>document</var>'s
+    <h3 id="algo-create-from-response"><dfn export
+    id="create-from-response">Create a Feature
+    Policy for a browsing <var>context</var> from <var>response</var></dfn></h3>
+    <p>Given a <a>browsing context</a> (<var>browsingContext</var>), <a>origin</a>
+    (<var>origin</var>), and a [=response=] (<var>response</var>), this algorithm returns a new
     <a>Feature Policy</a></p>
     <ol>
-      <li><a>Initialize <var>document</var>'s
-      Feature Policy</a></li>
-      <li>Let <var>inherited policy</var> be <var>document</var>'s Feature
-      Policy's <a>inherited policy</a>.</li>
-      <li>Let <var>declared policy</var> be a new ordered map.</li>
+      <li>Let <var>policy</var> be the result of running <a>Create a Feature Policy for a browsing
+      context</a> given <var>browsingContext</var>, and <var>origin</var>.</li>
       <li>Let <var>d</var> be the result of running <a
       href="#process-response-policy">Process response policy</a> on
-      <var>response</var> and <var>document</var>'s origin.</li>
+      <var>response</var> and <var>origin</var>.</li>
       <li>For each <var>feature</var> → <var>allowlist</var> of <var>d</var>:
         <ol>
-          <li>If <var>inherited policy</var>[<var>feature</var>] is true, then
-          set <var>declared policy</var>[<var>feature</var>] to
+          <li>If <var>policy</var>'s <a>inherited policy</a>[<var>feature</var>] is true, then
+          set <var>policy</var>'s <a>declared policy</a>[<var>feature</var>] to
           <var>allowlist</var>.</li>
         </ol>
       </li>
-      <li>Let <var>policy</var> be a new <a>feature policy</a>, with inherited
-      policy <var>inherited policy</var> and declared policy <var>declared
-      policy</var>.
-      </li>
+      <li>Return <var>policy</var>.</li>
+    </ol>
+  </section>
+  <section>
+    <h3 id="algo-initialize-from-response"><dfn export
+    id="initialize-from-response">Initialize <var>document</var>'s Feature
+    Policy from <var>response</var></dfn></h3>
+    <p>Given a [=response=] (<var>response</var>) and a <a>Document</a>
+    (<var>document</var>), this algorithm populates <var>document</var>'s
+    <a>Feature Policy</a></p>
+    <ol>
+      <li>Let <var>policy</var> be the result of running <a>Create a Feature Policy for a browsing
+      context from response</a> given <var>document</var>'s <a>browsing context</a>, <var>document</var>'s
+      <a>origin</a>, and <var>response</var>.</li>
       <li>
         Set <var>document</var>’s <a href="https://html.spec.whatwg.org/multipage/dom.html#concept-document-feature-policy">feature policy</a> to <var>policy</var>.
       </li>
     </ol>
   </section>
   <section>
-    <h3 id="algo-define-inherited-policy"><dfn>Define an inherited policy for
-    <var>feature</var> in <var>document</var></dfn></h3>
-    <p>Given a feature (<var>feature</var>) and a <a>Document</a>
-    (<var>document</var>), this algorithm returns the <a>inherited policy</a>
-    for that feature.</p>
+    <h3 id="algo-define-inherited-policy"><dfn id="define-inherited-policy">Define an inherited policy for
+    <var>feature</var> in <a>browsing context</a></dfn></h3>
+    <p>Given a feature (<var>feature</var>), an <a>origin</a> (<var>origin</var>), and
+    a <a>browsing context</a> (<var>browsingContext</var>), this algorithm returns the
+    <a>inherited policy</a> for that feature.</p>
     <ol>
-      <li>Let <var>context</var> be <var>document</var>'s <a>browsing
-      context</a>.</li>
-      <li>If <var>context</var> is the [=nested browsing context=] of a
+      <li>If <var>browsingContext</var> is the [=nested browsing context=] of a
         [=browsing context container=] <var>element</var>, return the result of
         executing <a>Define an inherited policy for feature in container at
-        origin</a> for <var>feature</var> in <var>context</var>'s <a>browsing
-        context container</a> at <var>document</var>'s
-        <a>origin</a>.</li>
+        origin</a> for <var>feature</var> in <var>browsingContext</var>'s <a>browsing
+        context container</a> at <var>origin</var>.</li>
       <li>Otherwise, return "<code>Enabled</code>".</li>
     </ol>
   </section>