Fix #227: Make createEvent("touchevent") sometimes throw

Browsers typically disable touch events on non-touch devices, and
there exists Web content that detects this difference using
createEvent.

Author: zcorpan

dom.bs

@@ -4982,6 +4982,13 @@ invoked, must run these steps:
     <tr><td>"<code>wheelevent</code>"<td>{{WheelEvent}}<td>[[!UIEVENTS]]
   </table>
 
+ <li>
+  If the user agent does not support the <var>constructor</var> interface, or has it disabled
+  in its current configuration, let <var>constructor</var> be null.
+
+  <p class=note>Typically user agents have the {{TouchEvent}} interface disabled in some
+  configurations.
+
  <li>If <var>constructor</var> is null, <a>throw</a> a
  {{NotSupportedError}}.
 

dom.html

@@ -2875,6 +2875,11 @@ <h3 class="heading settled" data-level="4.5" id="interface-document"><span class
         <td><code class="idl"><a data-link-type="idl">WheelEvent</a></code>
         <td><a data-link-type="biblio" href="#biblio-uievents">[UIEVENTS]</a> 
      </table>
+    <li>
+      If the user agent does not support the <var>constructor</var> interface, or has it disabled
+  in its current configuration, let <var>constructor</var> be null. 
+     <p class="note" role="note">Typically user agents have the <code class="idl"><a data-link-type="idl" href="https://www.w3.org/TR/touch-events/#touchevent-interface">TouchEvent</a></code> interface disabled in some
+  configurations. </p>
     <li>If <var>constructor</var> is null, <a data-link-type="dfn" href="https://heycam.github.io/webidl/#dfn-throw">throw</a> a <code class="idl"><a data-link-type="idl" href="https://heycam.github.io/webidl/#notsupportederror">NotSupportedError</a></code>. 
     <li>Let <var>event</var> be the result of <a data-link-type="dfn" href="#concept-event-constructor">invoking</a> the initial
  value of <var>constructor</var> with the empty string as argument. 
@@ -3172,7 +3177,7 @@ <h3 class="heading settled" data-level="4.9" id="interface-element"><span class=
          <p>Set <var>result</var> to <a data-link-type="abstract-op" href="https://tc39.github.io/ecma262/#sec-construct">Construct</a>(<var>C</var>). Rethrow any
      exceptions. </p>
         <li>
-         <p>If <var>result</var> does not implement the <code class="idl"><a data-link-type="idl" href="https://html.spec.whatwg.org/multipage/dom.html#htmlelement">HTMLElement</a></code> interface, <a data-link-type="dfn" href="https://heycam.github.io/webidl/#dfn-throw">throw</a> a <code class="idl"><a data-link-type="idl" href="https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror">TypeError</a></code> exception. </p>
+         <p>If <var>result</var> does not implement the <code class="idl"><a data-link-type="idl" href="https://html.spec.whatwg.org/multipage/dom.html#htmlelement">HTMLElement</a></code> interface, <a data-link-type="dfn" href="https://heycam.github.io/webidl/#dfn-throw">throw</a> a <code class="idl"><a data-link-type="idl">TypeError</a></code> exception. </p>
          <p class="note" role="note">This is meant to be a brand check to ensure that the object was allocated by the <code class="idl"><a data-link-type="idl" href="https://html.spec.whatwg.org/multipage/dom.html#htmlelement">HTMLElement</a></code> constructor. See <a href="https://github.com/heycam/webidl/issues/97">webidl #97</a> about making this more
       precise. </p>
         <li>
@@ -4918,7 +4923,7 @@ <h3 class="heading settled" data-level="8.1" id="dom-events-changes"><span class
    </ul>
    <h3 class="heading settled" data-level="8.2" id="dom-core-changes"><span class="secno">8.2. </span><span class="content">DOM Core</span><a class="self-link" href="#dom-core-changes"></a></h3>
    <p>These are the changes made to the features described in <cite>DOM Level 3 Core</cite>.</p>
-   <p><code class="idl"><a data-link-type="idl" href="https://heycam.github.io/webidl/#idl-DOMString">DOMString</a></code>, <code class="idl"><a data-link-type="idl" href="https://heycam.github.io/webidl/#dfn-domexception">DOMException</a></code>, and <code class="idl"><a data-link-type="idl" href="https://heycam.github.io/webidl/#common-domtimestamp">DOMTimeStamp</a></code> are now defined in Web IDL.</p>
+   <p><code class="idl"><a data-link-type="idl" href="https://heycam.github.io/webidl/#idl-DOMString">DOMString</a></code>, <code class="idl"><a data-link-type="idl" href="https://heycam.github.io/webidl/#dfn-DOMException">DOMException</a></code>, and <code class="idl"><a data-link-type="idl" href="https://heycam.github.io/webidl/#common-domtimestamp">DOMTimeStamp</a></code> are now defined in Web IDL.</p>
    <p><code class="idl"><a data-link-type="idl" href="#node">Node</a></code> now inherits from <code class="idl"><a data-link-type="idl" href="#eventtarget">EventTarget</a></code>.</p>
    <p><a data-link-type="dfn" href="#concept-node">Nodes</a> are implicitly <a data-link-type="dfn" href="#concept-node-adopt">adopted</a> across <a data-link-type="dfn" href="#concept-document">document</a> boundaries.</p>
    <p><a data-link-type="dfn" href="#concept-doctype">Doctypes</a> now always have a <a data-link-type="dfn" href="#concept-node-document">node document</a> and can be moved
@@ -6008,7 +6013,6 @@ <h3 class="no-num no-ref heading settled" id="index-defined-elsewhere"><span cla
     <a data-link-type="biblio">[ECMASCRIPT]</a> defines the following terms:
     <ul>
      <li><a href="https://tc39.github.io/ecma262/#sec-construct">Construct</a>
-     <li><a href="https://tc39.github.io/ecma262/#sec-native-error-types-used-in-this-standard-typeerror">TypeError</a>
     </ul>
    <li>
     <a data-link-type="biblio">[css-animations-1]</a> defines the following terms:
@@ -6078,7 +6082,19 @@ <h3 class="no-num no-ref heading settled" id="index-defined-elsewhere"><span cla
    <li>
     <a data-link-type="biblio">[WEBIDL]</a> defines the following terms:
     <ul>
+     <li><a href="https://heycam.github.io/webidl/#dfn-DOMException">DOMException</a>
      <li><a href="https://heycam.github.io/webidl/#idl-DOMString">DOMString</a>
+     <li><a href="https://heycam.github.io/webidl/#hierarchyrequesterror">HierarchyRequestError</a>
+     <li><a href="https://heycam.github.io/webidl/#inuseattributeerror">InUseAttributeError</a>
+     <li><a href="https://heycam.github.io/webidl/#indexsizeerror">IndexSizeError</a>
+     <li><a href="https://heycam.github.io/webidl/#invalidcharactererror">InvalidCharacterError</a>
+     <li><a href="https://heycam.github.io/webidl/#invalidnodetypeerror">InvalidNodeTypeError</a>
+     <li><a href="https://heycam.github.io/webidl/#invalidstateerror">InvalidStateError</a>
+     <li><a href="https://heycam.github.io/webidl/#namespaceerror">NamespaceError</a>
+     <li><a href="https://heycam.github.io/webidl/#notfounderror">NotFoundError</a>
+     <li><a href="https://heycam.github.io/webidl/#notsupportederror">NotSupportedError</a>
+     <li><a href="https://heycam.github.io/webidl/#syntaxerror">SyntaxError</a>
+     <li><a href="https://heycam.github.io/webidl/#wrongdocumenterror">WrongDocumentError</a>
     </ul>
   </ul>
   <h2 class="no-num no-ref heading settled" id="references"><span class="content">References</span><a class="self-link" href="#references"></a></h2>