Parse manifest file with app.service_worker.script.

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.
 
 // See c/c/e/features/* to understand this file, in particular feature.h,
 // simple_feature.h, and base_feature_provider.h.
 
 {
   "app": {
     "channel": "stable",
@@ skipping 24 matching lines @@
   "app.isolation": {
     "channel": "stable",
     // Platform apps always have isolated storage, thus they cannot specify it
     // via the manifest.
     "extension_types": ["legacy_packaged_app", "hosted_app"]
   },
   "app.launch": {
     "channel": "stable",
     "extension_types": ["legacy_packaged_app", "hosted_app"]
   },
+  "app.service_worker": {
+    "channel": "trunk",
+    "extension_types": ["platform_app"]
+  },
   "author": {
     "channel": "stable",
     "extension_types": "all"
   },
   "background": {
     "channel": "stable",
     "extension_types": [
       // Platform apps specify their background page via app.background.
       "extension", "legacy_packaged_app", "hosted_app"
     ]
@@ skipping 374 matching lines @@
       "extension_types": ["platform_app"],
       "location": "component"
     }
   ],
   "webview": {
     "channel": "stable",
     "extension_types": ["platform_app"],
     "min_manifest_version": 2
   }
 }