Add some closureised JS bindings for DevTools for use by headless embedder

headless/test/bindings_test.js

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+goog.require('chromium.DevTools.Connection');
+goog.require('chromium.DevTools.DOM');
+goog.require('chromium.DevTools.Runtime');
+goog.provide('chromium.BindingsTest');
+
+/**
+ * Evaluates 1+1 and returns the result over the chromium.DevTools.Connection.
+ */
+chromium.BindingsTest.evalOneAddOne = function() {
+  let connection = new chromium.DevTools.Connection(window.TabSocket);
+  let Runtime = new chromium.DevTools.Runtime(connection);
+  Runtime.Evaluate({'expression': '1+1'}).then(function(message) {
+    connection.sendDevToolsMessage(
+        '__Result',
+        {'result': JSON.stringify(message.result.value)});
+  });
+};
+
+chromium.BindingsTest.listenForChildNodeCountUpdated = function() {
+  let connection = new chromium.DevTools.Connection(window.TabSocket);
+  let DOM = new chromium.DevTools.DOM(connection);
+  DOM.OnChildNodeCountUpdated(function(params) {
+    connection.sendDevToolsMessage('__Result',
+                                   {'result': JSON.stringify(params)});
+  });
+  DOM.Enable().then(function() {

[dpapad, 2017/06/07 17:49:23]

Prefer Promise chaining over nesting where possible.

DOM.Enable().then(function() {
  return DOM.GetDocument({});
}).then(function() {
 // Create a new div which should trigger the event.
 let div = document.createElement('div');
 document.body.appendChild(div);
});

[alex clarke (OOO till 29th), 2017/06/08 10:33:16]

Done.

+    DOM.GetDocument({}).then(function(result) {

[dpapad, 2017/06/07 17:49:23]

|result| is not being used anywhere. Can you omit it?

[alex clarke (OOO till 29th), 2017/06/08 10:33:16]

Done.

+      // Create a new div which should trigger the event.
+      let div = document.createElement('div');
+      document.body.appendChild(div);
+    });
+  });
+};