Updating JSON Schema Compiler to add description field to schemas.

chrome/browser/performance_monitor/events.json

 // Copyright (c) 2012 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.
 
 [
   {
     "namespace": "events",
+    "description": "Performance monitor events",
     "types": [
       {
         "id": "ExtensionEvent",
         "type": "object",
         "description": "The event to describe a significant occurrence with an extension in Chrome, including installation, uninstallation, enablement, disablement, and update.",
         "properties": {
           "eventType": {"type": "integer", "description": "The type of the event."},
           "time": {"type": "number", "description": "The time at which the event was recorded."},
           "extensionId": {"type": "string", "description": "The extension's id."},
           "extensionName": {"type": "string", "description": "The extension's name."},
@@ skipping 30 matching lines @@
         "description": "The event to represent an unclean exit.",
         "properties": {
           "eventType": {"type": "integer", "description": "The type of the event."},
           "time": {"type": "number", "description": "The time at which the event was recorded."},
           "profileName": {"type": "string", "description": "The name of the profile which shutdown uncleanly."}
         }
       }
     ]
   }
 ]