Create a mechanism define declarative rules via the extension manifest.

chrome/common/extensions/api/_manifest_features.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.
 
 // This features file defines manifest keys implemented under src/chrome.
 // See extensions/common/features/* to understand this file, in particular
 // feature.h, simple_feature.h, and base_feature_provider.h.
 
 // To add a new whitelisted ID, SHA-1 it and force it to uppercase. In Bash:
 //
@@ skipping 78 matching lines @@
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app"]
   },
   "converted_from_user_script": {
     "channel": "stable",
     "extension_types": [
       "extension", "legacy_packaged_app", "hosted_app"
     ],
     "no_doc": true
   },
+  "event_rules": {
+    "channel": "stable",

[not at google - send to devlin, 2015/06/04 17:58:48]

Note to readers (no action needed): I don't think it's necessary to start this
in dev channel, it doesn't grant capabilities.

[danduong, 2015/06/04 19:56:07]

Acknowledged.

+    "extension_types": "all"

[not at google - send to devlin, 2015/06/04 17:58:48]

"all" is scary, but the right thing in this case. Could you add a comment here:

// "event_rules" does not grant any capabilities, it's just
// an optimisation for any API which uses events, so it's safe
// to expose to all extension types.
"extension_types": "all"

[danduong, 2015/06/04 19:10:58]

Done.

+  },
   "devtools_page": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app"]
   },
   "display_in_launcher": [
     {
       "channel": "stable",
       "extension_types": ["legacy_packaged_app", "platform_app", "hosted_app"],
       "location": "component"
     },
@@ skipping 151 matching lines @@
   },
   "update_url": {
     "channel": "stable",
     "extension_types": "all"
   },
   "url_handlers": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   }
 }