Add a StateManager for managing hotwording state based on various factors

chrome/browser/resources/hotword/manifest.json

 {
   // Extension ID: nbpagnldghgfoolbancepceaanlmhfmd
   "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDbHXRPiq2De9EJ+4pvNN6uE/D2avxrqyLSpA/Hq3II+btkPl1gboY3oUPTfevpVOFa90Y1c1b3/W682dXqybT0klIvFLKhdQx0LiVqSUQyIaDrwOCSo/ZcukbEwDRojegWymCjHvX6WZk4kKZzTJYzY1vrp0TWKLhttEMN9KFmowIDAQAB",
 
   "name": "Hotword triggering",
   "version": "0.0.1.0",

[rpetterson, 2014/08/26 19:16:59]

This should be incremented for the new events to take effect in previous
installs.

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

   "manifest_version": 2,
 
   "background": {
     "scripts": [
       "chrome://resources/js/cr.js",
       "chrome://resources/js/util.js",
       "chrome://resources/js/cr/event_target.js",
       "constants.js",
       "nacl_manager.js",
+      "state_manager.js",
       "manager.js"
     ],
     "persistent": false
   },
 
   "permissions": [
     "*://*.google.com/*",
     "chrome://newtab/",
     "chrome://resources/",
+    "audioCapture",
     "hotwordPrivate",
+    "management",
     "tabs"
   ],
 
   "externally_connectable": {
     "matches": [
       "*://*.google.com/*",
       "chrome://newtab/"
     ]
   },
 
   "import": [
     {
       // TODO(amistry): For now, use a locally modified version of the external
       // hotword extension. Replace with the ID of the new shared module
       // containing the hotword detector.
       "id": "bepbmhgboaologfdajaanbcjmnhjmhfn"
     }
   ],
 
+  "content_security_policy": "object-src 'none'; script-src chrome://resources 'self'",
   "minimum_chrome_version": "38"
 }