Added lang member (closes #322)

index.html

@@ -110,6 +110,7 @@ <h3>
         </p>
         <pre class="example highlight json" title="typical manifest">
 {
+  "lang": "en",
   "name": "Super Racer 2000",
   "short_name": "Racer2K",
   "icons": [{
@@ -706,6 +707,7 @@ <h3>
 Content-Type: application/manifest+json
 
 {
+  "lang": "en",
   "name": "Super Racer 2000",
   "start_url": "/start.html",
   "display": "fullscreen",
@@ -838,6 +840,10 @@ <h3>
           of running the <a>steps for processing the <code>name</code>
           member</a> with <var>manifest</var> as the argument.
           </li>
+          <li>Let <var>language</var> of <var>parsed manifest</var> be the
+          result of running the <a>steps for processing the <code>lang</code>
+          member</a> with <var>manifest</var> as the argument.
+          </li>
           <li>Let <var>short name</var> of <var>parsed manifest</var> be the
           result of running the <a>steps for processing the
           <code>short_name</code> member</a> with <var>manifest</var> as the
@@ -940,6 +946,41 @@ <h2>
         Every manifest has an associated <dfn>manifest URL</dfn>, which the
         [[!URL]] from which the <a>manifest</a> was fetched.
       </p>
+      <section>
+        <h3>
+          <code title="">lang</code> member
+        </h3>
+        <p>
+          The <dfn id="member-lang"><code>lang</code></dfn> member is a
+          [[!BCP47]] language tag (string) that specifies the primary language
+          for the values of the manifest's <code>name</code> and
+          <code>short_name</code> members.
+        </p>
+        <p>
+          The <dfn>steps for processing the <code>lang</code> member</dfn> is
+          given by the following algorithm. The algorithm takes a
+          <var>manifest</var> as an argument. This algorithm returns a string
+          or <code>undefined</code>.
+        </p>
+        <ol>
+          <li>Let <var>value</var> be the result of calling the
+          <a>[[\GetOwnProperty]]</a> internal method of <var>manifest</var>
+          with argument "<code>name</code>".
+          </li>
+          <li>If <a>Type</a>(<var>value</var>) is not "string":
+            <ol>
+              <li>If <a>Type</a>(<var>value</var>) is not "undefined",
+              optionally <a>issue a developer warning</a> that the type is not
+              supported.
+              </li>
+              <li>Return <code>undefined</code>.
+              </li>
+            </ol>
+          </li>
+          <li>Otherwise, <a>Trim</a>(<var>value</var>) and return the result.
+          </li>
+        </ol>
+      </section>
       <section>
         <h3>
           <code title="">name</code> member