Update json_schema_compiler to handle the Automation extension API

chrome/browser/resources/chromeos/chromevox/cvox2/background/custom_automation_event.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.
+
+/**
+ * @fileoverview Custom Automation Event.
+ *
+ * An object similar to a chrome.automation.AutomationEvent that we can
+ * construct, unlike the object from the extension system.
+ */
+
+goog.provide('CustomAutomationEvent');
+
+/**
+ * An object we can use instead of a chrome.automation.AutomationEvent.
+ * @constructor
+ * @param {chrome.automation.EventType} type The event type.
+ * @param {!chrome.automation.AutomationNode} target The event target.
+ * @param {string} eventFrom The source of this event.

[Dan Beam, 2017/01/10 22:54:43]

could AutomationEvent just be an interface that gets @implemented by
CustomAutomationEvent?

[dmazzoni, 2017/01/11 22:20:41]

I don't think I could do that without major changes and maybe breaking
backwards compatibility...but I can do @extends {AutomationEvent} and
that works great, thanks.

+ */
+CustomAutomationEvent = function(type, target, eventFrom) {

[Dan Beam, 2017/01/10 22:54:43]

var CustomAutomationEvent = function(...) {
};

or

function CustomAutomationEvent(...) {
}

[dmazzoni, 2017/01/11 22:20:41]

Done.

+  this.type = type;
+  this.target = target;
+  this.eventFrom = eventFrom;
+};