Permit structured serialization of BigInt

* Adds BigInt to the safelist of primitives permitted for serialization
* Adds serialization of BigInt wrappers, analogous to other wrappers

Tests: web-platform-tests/wpt#9565

Author: littledan

source

@@ -3065,7 +3065,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x-href="https://tc39.github.io/ecma262/#table-49">The <var>TypedArray</var> Constructors</dfn> table</li>
     </ul>
 
-    <p>Users agents that support JavaScript must also implement the <cite>import()</cite> proposal.
+    <p>User agents that support JavaScript must also implement the <cite>import()</cite> proposal.
     The following terms are defined there, and used in this specification: <ref spec=JSIMPORT></p>
 
     <ul class="brief">
@@ -3074,14 +3074,16 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li>The <dfn data-x-href="https://tc39.github.io/proposal-dynamic-import/#sec-finishdynamicimport">FinishDynamicImport</dfn> abstract operation</li>
     </ul>
 
-    <p>Users agents that support JavaScript must also implement the <cite>import.meta</cite>
+    <p>User agents that support JavaScript must also implement the <cite>import.meta</cite>
     proposal. The following term is defined there, and used in this specification: <ref
     spec=JSIMPORTMETA></p>
 
     <ul class="brief">
      <li>The <dfn data-x="js-HostGetImportMetaProperties" data-x-href="https://tc39.github.io/proposal-import-meta/#sec-hostgetimportmetaproperties">HostGetImportMetaProperties</dfn> abstract operation</li>
     </ul>
 
+    <p>User agents that support JavaScript must also implement the <cite>BigInt</cite> proposal. <ref
+    spec=JSBIGINT></p>
    </dd>
 
 
@@ -8127,7 +8129,8 @@ interface <dfn>DOMStringList</dfn> {
    <li><p>Let <var>deep</var> be false.</p></li>
 
    <li><p>If <span data-x="js-Type">Type</span>(<var>value</var>) is Undefined, Null, Boolean,
-   String, or Number, then return { [[Type]]: "primitive", [[Value]]: <var>value</var> }.</p></li>
+   Number, BigInt, or String, then return { [[Type]]: "primitive",
+   [[Value]]: <var>value</var> }. <ref spec=JSBIGINT></p></li>
 
    <li><p>If <span data-x="js-Type">Type</span>(<var>value</var>) is Symbol, then throw a
    <span>"<code>DataCloneError</code>"</span> <code>DOMException</code>.</p></li>
@@ -8141,6 +8144,10 @@ interface <dfn>DOMStringList</dfn> {
    <var>serialized</var> to { [[Type]]: "Number", [[NumberData]]: <var>value</var>.[[NumberData]]
    }.</p></li>
 
+   <li><p>Otherwise, if <var>value</var> has a [[BigIntData]]
+   internal slot, then set <var>serialized</var> to { [[Type]]: "BigInt", [[BigIntData]]:
+   <var>value</var>.[[BigIntData]] }. <ref spec=JSBIGINT></p></li>
+
    <li><p>Otherwise, if <var>value</var> has a [[StringData]] internal slot, then set
    <var>serialized</var> to { [[Type]]: "String", [[StringData]]: <var>value</var>.[[StringData]]
    }.</p></li>
@@ -8538,24 +8545,28 @@ o.myself = o;</pre>
    <li><p>If <var>serialized</var>.[[Type]] is "primitive", then set <var>value</var> to
    <var>serialized</var>.[[Value]].</p>
 
-   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "Boolean", then set <var>value</var> to a new Boolean object in
-   <var>targetRealm</var> whose [[BooleanData]] internal slot value is
+   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "Boolean", then set <var>value</var> to a
+   new Boolean object in <var>targetRealm</var> whose [[BooleanData]] internal slot value is
    <var>serialized</var>.[[BooleanData]].</p></li>
 
-   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "Number", then set <var>value</var> to a new Number object in
-   <var>targetRealm</var> whose [[NumberData]] internal slot value is
+   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "Number", then set <var>value</var> to a
+   new Number object in <var>targetRealm</var> whose [[NumberData]] internal slot value is
    <var>serialized</var>.[[NumberData]].</p></li>
 
-   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "String", then set <var>value</var> to a new String object in
-   <var>targetRealm</var> whose [[StringData]] internal slot value is
+   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "BigInt", then set <var>value</var> to a
+   new BigInt object in <var>targetRealm</var> whose [[BigIntData]] internal slot value is
+   <var>serialized</var>.[[BigIntData]]. <ref spec=JSBIGINT></p></li>
+
+   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "String", then set <var>value</var> to a
+   new String object in <var>targetRealm</var> whose [[StringData]] internal slot value is
    <var>serialized</var>.[[StringData]].</p></li>
 
-   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "Date", then set <var>value</var> to a new Date object in
-   <var>targetRealm</var> whose [[DateValue]] internal slot value is
+   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "Date", then set <var>value</var> to a new
+   Date object in <var>targetRealm</var> whose [[DateValue]] internal slot value is
    <var>serialized</var>.[[DateValue]].</p></li>
 
-   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "RegExp", then set <var>value</var> to a new RegExp object in
-   <var>targetRealm</var> whose [[RegExpMatcher]] internal slot value is
+   <li><p>Otherwise, if <var>serialized</var>.[[Type]] is "RegExp", then set <var>value</var> to a
+   new RegExp object in <var>targetRealm</var> whose [[RegExpMatcher]] internal slot value is
    <var>serialized</var>.[[RegExpMatcher]], whose [[OriginalSource]] internal slot value is
    <var>serialized</var>.[[OriginalSource]], and whose [[OriginalFlags]] internal slot value is
    <var>serialized</var>.[[OriginalFlags]].</p></li>
@@ -120209,6 +120220,9 @@ INSERT INTERFACES HERE
    <dt id="refsJPEG">[JPEG]</dt>
    <dd><cite><a href="https://www.w3.org/Graphics/JPEG/jfif3.pdf">JPEG File Interchange Format</a></cite>, E. Hamilton.</dd>
 
+   <dt id="refsJSBIGINT">[JSBIGINT]</dt>
+   <dd><cite><a href="https://tc39.github.io/proposal-bigint/">BigInt</a></cite>. Ecma International.</dd>
+
    <dt id="refsJSIMPORT">[JSIMPORT]</dt>
    <dd><cite><a href="https://tc39.github.io/proposal-dynamic-import/">import()</a></cite>. Ecma International.</dd>