'Moved all documentation from old .dartdoc files.'

tools/dom/docs/docs.json

 {
   "dart.dom.html": {
     "CanvasGradient": {
       "comment": [
         "/**",
         " * An opaque canvas object representing a gradient.",
         " *",
         " * Created by calling [createLinearGradient] or [createRadialGradient] on a",
         " * [CanvasRenderingContext2D] object.",
         " *",
@@ skipping 232 matching lines @@
         " *     document.body.elements.add(elem);",
         " *",
         " * See also:",
         " *",
         " * * [HTML <div> element](http://www.w3.org/TR/html-markup/div.html) from W3C.",
         " * * [Block-level element](http://www.w3.org/TR/CSS2/visuren.html#block-boxes) from W3C.",
         " * * [Inline-level element](http://www.w3.org/TR/CSS2/visuren.html#inline-boxes) from W3C.",
         " */"
       ]
     },
+    "WebSocket": {
+      "comment": [
+        "/**",
+        " * Use the WebSocket interface to connect to a WebSocket,",
+        " * and to send and receive data on that WebSocket.",
+        " *",
+        " * To use a WebSocket in your web app, first create a WebSocket object,",
+        " * passing the WebSocket URL as an argument to the constructor.",
+        " *",
+        " *     var webSocket = new WebSocket('ws://127.0.0.1:1337/ws');",
+        " *",
+        " * To send data on the WebSocket, use the [send] method.",
+        " *",
+        " *     if (webSocket != null && webSocket.readyState == WebSocket.OPEN) {",
+        " *       webSocket.send(data);",
+        " *     } else {",
+        " *       print('WebSocket not connected, message $data not sent');",
+        " *     }",
+        " *",
+        " * To receive data on the WebSocket, register a listener for message events.",
+        " *",
+        " *     webSocket.on.message.add((MessageEvent e) {",
+        " *       receivedData(e.data);",
+        " *     });",
+        " *",
+        " * The message event handler receives a [MessageEvent] object",
+        " * as its sole argument.",
+        " * You can also define open, close, and error handlers,",
+        " * as specified by [WebSocketEvents].",
+        " *",
+        " * For more information, see the",
+        " * [WebSockets](http://www.dartlang.org/docs/library-tour/#html-websockets)",
+        " * section of the library tour and",
+        " * [Introducing WebSockets](http://www.html5rocks.com/en/tutorials/websockets/basics/),",
+        " * an HTML5Rocks.com tutorial.",
+        " */"
+      ]
+    },
     "XMLHttpRequest": {
       "members": {
         "abort": [
           "/**",
           "   * Stop the current request.",
           "   *",
           "   * The request can only be stopped if readyState is `HEADERS_RECIEVED` or",
           "   * `LOADING`. If this method is not in the process of being sent, the method",
           "   * has no effect.",
           "   */"
@@ skipping 156 matching lines @@
           "   * is the (more verbose) equivalent of",
           "   *",
           "   *     var request = new HttpRequest.get('http://dartlang.org',",
           "   *         (event) => print('Request complete'));",
           "   */"
         ]
       }
     }
   }
 }