Ensure that 'noopener' does not reuse a browsing context

WIP: All of this would benefit from more substantial refactoring, but
let's decide that this is the right way to approach things first.

#1826

source

@@ -18647,8 +18647,8 @@ interface <dfn>HTMLAnchorElement</dfn> : <span>HTMLElement</span> {
  <span>triggered by user activation</span>; or, if the user has not indicated a specific
  <span>browsing context</span> for following the link, and the element's <code
  data-x="attr-hyperlink-target">target</code> attribute is present, and applying <span>the rules
- for choosing a browsing context given a browsing context name</span>, using the value of the
- <code data-x="attr-hyperlink-target">target</code> attribute as the browsing context name, would
+ for choosing a browsing context</span>, using the value of the <code
+ data-x="attr-hyperlink-target">target</code> attribute as the browsing context name, would
  result in there not being a chosen browsing context, then run these substeps:</p>
 
  <ol>
@@ -22232,20 +22232,27 @@ interface <dfn>HTMLHyperlinkElementUtils</dfn> {
  <span>one permitted sandboxed navigator</span>.</p>
 
  <p>Otherwise, if <var>subject</var> is an <code>a</code> or <code>area</code> element
- that has a <code data-x="attr-hyperlink-target">target</code> attribute, then let <var>target</var> be the <span>browsing context</span> that is chosen by applying <span>the
- rules for choosing a browsing context given a browsing context name</span>, using the value of
- the <code data-x="attr-hyperlink-target">target</code> attribute as the browsing context name. If
- these rules result in the creation of a new <span>browsing context</span>, set <var>replace</var> to true.</p>
+ that has a <code data-x="attr-hyperlink-target">target</code> attribute, then let
+ <var>target</var> be the <span>browsing context</span> that is chosen by applying <span>the
+ rules for choosing a browsing context</span>, using the value of the <code
+ data-x="attr-hyperlink-target">target</code> attribute as the browsing context name, and
+ a disown opener flag of true if the element has a <code data-x="attr-hyperlink-rel">rel</code>
+ attribute whose value is "<code data-x="">noopener</code>" or "<code
+ data-x="">noreferrer</code>", and false otherwise. If these rules result in the creation of a
+ new <span>browsing context</span>, set <var>replace</var> to true.</p>
 
  <p>Otherwise, if <var>target</var> is an <code>a</code> or <code>area</code> element
  with no <code data-x="attr-hyperlink-target">target</code> attribute, but the
  <code>Document</code> contains a <code>base</code> element with a <code
  data-x="attr-base-target">target</code> attribute, then let <var>target</var> be the
  <span>browsing context</span> that is chosen by applying <span>the rules for choosing a browsing
- context given a browsing context name</span>, using the value of the <code
- data-x="attr-base-target">target</code> attribute of the first such <code>base</code> element as
- the browsing context name. If these rules result in the creation of a new <span>browsing
- context</span>, set <var>replace</var> to true.</p> <!-- c.f. concept-fs-target -->
+ context</span>, using the value of the <code data-x="attr-base-target">target</code> attribute
+ of the first such <code>base</code> element as the browsing context name, and a disown opener
+ flag of true if the element has a <code data-x="attr-hyperlink-rel">rel</code>
+ attribute whose value is "<code data-x="">noopener</code>" or "<code
+ data-x="">noreferrer</code>", and false otherwise. If these rules result in the creation of a
+ new <span>browsing context</span>, set <var>replace</var> to true.</p>
+ <!-- c.f. concept-fs-target -->
 
  <p>Otherwise, let <var>target</var> be <var>source</var>.</p>
 
@@ -37493,10 +37500,9 @@ interface <dfn>HTMLAreaElement</dfn> : <span>HTMLElement</span> {
  attribute and the algorithm is not <span>triggered by user activation</span>; or, if the user
  has not indicated a specific <span>browsing context</span> for following the link, and the
  element's <code data-x="attr-hyperlink-target">target</code> attribute is present, and applying
- <span>the rules for choosing a browsing context given a browsing context name</span>, using the
- value of the <code data-x="attr-hyperlink-target">target</code> attribute as the browsing
- context name, would result in there not being a chosen browsing context, then run these
- substeps:</p>
+ <span>the rules for choosing a browsing context</span>, using the value of the <code
+ data-x="attr-hyperlink-target">target</code> attribute as the browsing context name, would
+ result in there not being a chosen browsing context, then run these substeps:</p>
 
  <ol>
 
@@ -54768,10 +54774,10 @@ fur
 
  <li><p>If the user indicated a specific <span>browsing context</span> to use when submitting the
  form, then let <var>target browsing context</var> be that <span>browsing context</span>.
- Otherwise, apply <span>the rules for choosing a browsing context given a browsing context
- name</span> using <var>target</var> as the name and <var>form browsing
- context</var> as the context in which the algorithm is executed, and let <var>target
- browsing context</var> be the resulting <span>browsing context</span>.</p></li>
+ Otherwise, apply <span>the rules for choosing a browsing context</span> using <var>target</var>
+ as the name and <var>form browsing context</var> as the context in which the algorithm is
+ executed, and let <var>target browsing context</var> be the resulting <span>browsing
+ context</span>.</p></li>
 
  <li><p>If <var>target browsing context</var> was created in the previous step, or,
  alternatively, if the <var>form document</var> has not yet <span>completely
@@ -77856,15 +77862,16 @@ console.assert(iframeWindow.frameElement === null);
 
  <p class="tablenote"><small>Most of the restrictions on sandboxed browsing contexts are applied by
  other algorithms, e.g. the <span data-x="navigate">navigation</span> algorithm, not <span>the rules
- for choosing a browsing context given a browsing context name</span> given below.</small></p>
+ for choosing a browsing context</span> given below.</small></p>
 
  <div w-nodev>
 
  <hr>
 
- <p><dfn>The rules for choosing a browsing context given a browsing context name</dfn> are as
- follows. The rules assume that they are being applied in the context of a <span>browsing
- context</span>, as part of the execution of a <span data-x="concept-task">task</span>.</p>
+ <p><dfn>The rules for choosing a browsing context</dfn> given a browsing context name and disown
+ opener flag are as follows. The rules assume that they are being applied in the context of a
+ <span>browsing context</span>, as part of the execution of a <span
+ data-x="concept-task">task</span>.</p>
 
  <ol>
 
@@ -77890,10 +77897,10 @@ console.assert(iframeWindow.frameElement === null);
  browsing context whose <span data-x="browsing context name">name</span> is the same as the given
  browsing context name, and the current browsing context is <span>familiar with</span> that
  browsing context, and the user agent determines that the two browsing contexts are related
- enough that it is ok if they reach each other, then that browsing context must be the chosen
- one. If there are multiple matching browsing contexts, the user agent should select one in some
- arbitrary consistent manner, such as the most recently opened, most recently focused, or more
- closely related.</p>
+ enough that it is ok if they reach each other, and the disown opener flag is false, then that
+ browsing context must be the chosen one. If there are multiple matching browsing contexts, the
+ user agent should select one in some arbitrary consistent manner, such as the most recently
+ opened, most recently focused, or more closely related.</p>
 
  </li>
 
@@ -77941,11 +77948,11 @@ console.assert(iframeWindow.frameElement === null);
  create a new browsing context:</dt>
 
  <dd>
- <p>A new <span>auxiliary browsing context</span> must be created, with the <span>opener
- browsing context</span> being the current one. If the given browsing context name is not
- <code data-x="">_blank</code>, then the new auxiliary browsing context's name must be the
- given browsing context name (otherwise, it has no name). The chosen browsing context must be
- this new browsing context.</p>
+ <p>A new <span>top-level browsing context</span> must be created. Its <span>opener
+ browsing context</span> is the current one if the disown opener flag is false, and empty
+ otherwise. If the given browsing context name is not <code data-x="">_blank</code>, then the
+ new browsing context's name must be the given browsing context name (otherwise, it has no
+ name). The chosen browsing context must be this new browsing context.</p>
 
  <p class="note">If the newly created <span>browsing context</span> is immediately <span
  data-x="navigate">navigated</span>, then the navigation will be done with <span>replacement
@@ -78626,6 +78633,10 @@ callback <dfn>FrameRequestCallback</dfn> = void (<span>DOMHighResTimeStamp</span
  <li><p>If <var>target</var> is the empty string, let it be the string "<code
  data-x="">_blank</code>" instead.</p></li>
 
+ <li><p>Let <var>disown opener</var> be true if the result of <span data-x="split a string on
+ commas">splitting <var>features</var> on commas</span> contains the token "<code
+ data-x="">noopener</code>"
+
  <li>
 
  <p>If the user has indicated a preference for which <span>browsing context</span> to navigate,
@@ -78649,19 +78660,19 @@ callback <dfn>FrameRequestCallback</dfn> = void (<span>DOMHighResTimeStamp</span
  holds the control key down, the user agent could override the selection of the target browsing
  context to instead target a new tab.</p>
 
- <p>Otherwise, apply <span>the rules for choosing a browsing context given a browsing context
- name</span> using <var>target</var> as the name and <var>source browsing context</var> as the
- context in which the algorithm is executed. If this results in there not being a chosen browsing
- context, then throw an <span>"<code>InvalidAccessError</code>"</span> <code>DOMException</code>
- and abort these steps. Otherwise, let <var>target browsing context</var> be the <span>browsing
- context</span> so obtained.</p>
+ <p>Otherwise, apply <span>the rules for choosing a browsing context</span> using
+ <var>target</var> as the name, <var>disown opener</var>, and <var>source browsing context</var>
+ as the context in which the algorithm is executed. If this results in there not being a chosen
+ browsing context, then throw an <span>"<code>InvalidAccessError</code>"</span>
+ <code>DOMException</code> and abort these steps. Otherwise, let <var>target browsing
+ context</var> be the <span>browsing context</span> so obtained.</p>
 
  </li>
 
  <li><p>If <var>target browsing context</var> was just created, either as part of <span>the rules
- for choosing a browsing context given a browsing context name</span> or due to the user
- indicating a preference for navigating a new <span>top-level browsing context</span>, then let
- <var>new</var> be true. Otherwise, let it be false.</p></li>
+ for choosing a browsing context</span> or due to the user indicating a preference for navigating
+ a new <span>top-level browsing context</span>, then let <var>new</var> be true. Otherwise, let it
+ be false.</p></li>
 
  <li><p>Interpret <var>features</var> <span data-x="dom-open-features">as defined in the CSSOM
  View specification</span>. <ref spec="CSSOMVIEW"></p></li>
@@ -78721,9 +78732,8 @@ callback <dfn>FrameRequestCallback</dfn> = void (<span>DOMHighResTimeStamp</span
 
  <ol>
 
- <li><p>If the result of <span data-x="split a string on commas">splitting <var>features</var>
- on commas</span> contains the token "<code data-x="">noopener</code>", <span data-x="disowned
- its opener">disown <var>target browsing context</var>'s opener</span>, and return <code
+ <li><p>If <var>disown opener</var> is true, <span data-x="disowned its opener">disown
+ <var>target browsing context</var>'s opener</span>, and return <code
  data-x="">null</code>.</p></li>
 
  <li><p>Otherwise, return the <code>WindowProxy</code> object of <var>target browsing
@@ -80196,7 +80206,7 @@ callback <dfn>FrameRequestCallback</dfn> = void (<span>DOMHighResTimeStamp</span
  <p>Every <span>top-level browsing context</span> has a <dfn>popup sandboxing flag set</dfn>, which
  is a <span>sandboxing flag set</span>. When a <span>browsing context</span> is created, its
  <span>popup sandboxing flag set</span> must be empty. It is populated by <span>the rules for
- choosing a browsing context given a browsing context name</span>.</p>
+ choosing a browsing context</span>.</p>
 
  <p>Every <span>browsing context</span> that is a <span>nested browsing context</span> has an
  <dfn><code>iframe</code> sandboxing flag set</dfn>, which is a <span>sandboxing flag set</span>.