Remove dead script_badge code.

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 215 matching lines @@
   "plugins": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app", "hosted_app"]
   },
   "requirements": {
     "channel": "stable",
     "extension_types": [
       "extension", "legacy_packaged_app", "hosted_app", "platform_app"
     ]
   },
-  "script_badge": {
-    "channel": "trunk",
-    "extension_types": ["extension"]
-  },
   "short_name": {
     "channel": "stable",
     "extension_types": "all"
   },
   "signature": {
     "channel": "stable",
     "extension_types": "all"
   },
   "spellcheck": {
     "channel": "dev",
@@ skipping 33 matching lines @@
   },
   "update_url": {
     "channel": "stable",
     "extension_types": "all"
   },
   "url_handlers": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   }
 }