Add the enterkeyhint="" attribute

This allows an author to configure what type of icon is displayed in
place of the enter key on virtual keyboards.

Tests: web-platform-tests/wpt#12972

source

@@ -11364,6 +11364,7 @@ https://software.hixie.ch/utilities/js/live-dom-viewer/?%3C%21DOCTYPE%20HTML%3E%
    <li><code data-x="attr-contenteditable">contenteditable</code></li>
    <li><code data-x="attr-dir">dir</code></li>
    <li><code data-x="attr-draggable">draggable</code></li>
+   <li><code data-x="attr-enterkeyhint">enterkeyhint</code></li>
    <li><code data-x="attr-hidden">hidden</code></li>
    <li><code data-x="attr-inputmode">inputmode</code></li>
    <li><code data-x="attr-is">is</code></li>
@@ -73699,6 +73700,7 @@ addShortcutKeyLabel(document.getElementById('c'));</code></pre>
 
   <pre><code class="idl" data-x="">interface mixin <dfn>ElementContentEditable</dfn> {
   [<span>CEReactions</span>] attribute DOMString <span data-x="dom-contentEditable">contentEditable</span>;
+  [<span>CEReactions</span>] attribute DOMString <span data-x="dom-enterKeyHint">enterKeyHint</span>;
   readonly attribute boolean <span data-x="dom-isContentEditable">isContentEditable</span>;
   [<span>CEReactions</span>] attribute DOMString <span data-x="dom-inputMode">inputMode</span>;
 };</code></pre>
@@ -74377,6 +74379,70 @@ body { display:none }
 
   </div>
 
+  <h4>Input modalities: the <code data-x="attr-enterkeyhint">enterkeyhint</code>
+  attribute</h4>
+
+  <p>User agents can support the <code data-x="attr-enterkeyhint">enterkeyhint</code>
+  attribute on form controls (such as the value of <code>textarea</code> elements), or in elements
+  in an <span>editing host</span> (e.g., using <code
+  data-x="attr-contenteditable">contenteditable</code>).</p>
+
+  <p>The <dfn><code data-x="attr-enterkeyhint">enterkeyhint</code></dfn> content attribute is an
+  <span>enumerated attribute</span> that specifies what action label (or icon) to present for the
+  enter key on virtual keyboards. This allows authors to customize the presentation of the enter key
+  in order to make it more helpful for users.</p>
+
+  <table>
+   <thead>
+    <tr>
+     <th> Keyword
+     <th> Description
+   <tbody>
+    <tr>
+     <td><dfn><code data-x="attr-enterkeyhint-keyword-enter">enter</code></dfn>
+     <td>The user agent should present a cue for the operation 'enter', typically
+     inserting a new line.
+    <tr>
+     <td><dfn><code data-x="attr-enterkeyhint-keyword-done">done</code></dfn>
+     <td>The user agent should present a cue for the operation 'done', typically
+     meaning there is nothing more to input and the IME will be closed.
+    <tr>
+     <td><dfn><code data-x="attr-enterkeyhint-keyword-go">go</code></dfn>
+     <td> The user agent should present a cue for the operation 'go', typically
+     meaning to take the user to the target of the text they typed.
+    <tr>
+     <td><dfn><code data-x="attr-enterkeyhint-keyword-next">next</code></dfn>
+     <td>The user agent should present a cue for the operation 'next', typically
+     taking the user to the next field that will accept text.
+    <tr>
+     <td><dfn><code data-x="attr-enterkeyhint-keyword-previous">previous</code></dfn>
+     <td>The user agent should present a cue for the operation 'previous', typically
+     taking the user to the previous field that will accept text.
+    <tr>
+     <td><dfn><code data-x="attr-enterkeyhint-keyword-search">search</code></dfn>
+     <td>The user agent should present a cue for the operation 'search', typically
+     taking the user to the results of searching for the text they have typed.
+    <tr>
+     <td><dfn><code data-x="attr-enterkeyhint-keyword-send">send</code></dfn>
+     <td> The user agent should present a cue for the operation 'send', typically
+     delivering the text to its target.
+  </table>
+
+  <div w-nodev>
+
+  <p>The <dfn><code data-x="dom-enterKeyHint">enterKeyHint</code></dfn> IDL attribute must
+  <span>reflect</span> the <code data-x="attr-enterkeyhint">enterkeyhint</code> content
+  attribute, <span>limited to only known values</span>.</p>
+
+  <p>When <code data-x="attr-enterkeyhint">enterkeyhint</code> is unspecified (or is in a state not
+  supported by the user agent), the user agent should determine the default action label (or icon)
+  to present. Contextual information such as the <code data-x="attr-inputmode">inputmode</code>,
+  <code data-x="attr-input-type">type</code>, or <code data-x="attr-input-pattern">pattern</code>
+  attributes should be used to determine which action label (or icon) to present on the virtual
+  keyboard.</p>
+
+  </div>
+
   <h3 split-filename="dnd" id="dnd"><dfn>Drag and drop</dfn></h3>
 
 <!-- v2: ideas for drag and drop:
@@ -118274,6 +118340,17 @@ interface <dfn>External</dfn> {
      <td> <code data-x="attr-fs-enctype">form</code>
      <td> Entry list encoding type to use for <span>form submission</span>
      <td> "<code data-x="attr-fs-enctype-urlencoded">application/x-www-form-urlencoded</code>"; "<code data-x="attr-fs-enctype-formdata">multipart/form-data</code>"; "<code data-x="attr-fs-enctype-text">text/plain</code>"
+    <tr>
+     <th> <code data-x="">enterkeyhint</code>
+     <td> <span data-x="attr-enterkeyhint">HTML elements</span>
+     <td> Hint for selecting an enter key action
+     <td> "<code data-x="attr-enterkeyhint-keyword-enter">enter</code>";
+          "<code data-x="attr-enterkeyhint-keyword-done">done</code>";
+          "<code data-x="attr-enterkeyhint-keyword-go">go</code>";
+          "<code data-x="attr-enterkeyhint-keyword-next">next</code>";
+          "<code data-x="attr-enterkeyhint-keyword-previous">previous</code>";
+          "<code data-x="attr-enterkeyhint-keyword-search">search</code>"
+          "<code data-x="attr-enterkeyhint-keyword-send">send</code>"
     <tr>
      <th> <code data-x="">for</code>
      <td> <code data-x="attr-label-for">label</code>