Added Area Element class doc.

tools/dom/docs/docs.json

Index: tools/dom/docs/docs.json
diff --git a/tools/dom/docs/docs.json b/tools/dom/docs/docs.json
index 89087ea78dcce4d6570073e8a86a7bf6fedc6eb9..cbc8a7dae1bdb0849f31919bcba8cd05b7951686 100644
--- a/tools/dom/docs/docs.json
+++ b/tools/dom/docs/docs.json
@@ -159,6 +159,20 @@
         ]
       }
     },
+    "HTMLAreaElement": {
+      "comment": [
+        "/**",
+        " * DOM Area Element, which links regions of an image map with a hyperlink.",
+        " *",
+        " * The element can also define an uninteractive region of the map.",
+        " *",
+        " * See also:",
+        " *",
+        " * * [<area>](https://developer.mozilla.org/en-US/docs/HTML/Element/area)",
+        " * on MDN.",
+        " */"
+      ]
+    },
     "HTMLCanvasElement": {
       "members": {
         "height": [