Add getSelf method to management API to use without the "management" permission.

chrome/common/extensions/api/_api_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 extension APIs implemented under src/chrome.
 // See extensions/common/features/* to understand this file, in particular
 // feature.h, simple_feature.h, and base_feature_provider.h.
 //
 // Note that specifying "web_page", "blessed_web_page", or "all" as a context
 // type will require manually updating chrome/renderer/resources/dispatcher.cc.
@@ skipping 526 matching lines @@
   },
   "management": {
     "dependencies": ["permission:management"],
     "contexts": ["blessed_extension"]
   },
   "management.getPermissionWarningsByManifest": {
     "dependencies": [],
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app", "platform_app"]
   },
+  "management.getSelf": {
+    "dependencies": [],
+    "channel": "stable",
+    "extension_types": ["extension", "legacy_packaged_app", "platform_app"]
+  },
   "management.uninstallSelf": {
     "dependencies": [],
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app", "platform_app"]
   },
   // This is not a real API, only here for documentation purposes.
   // See http://crbug.com/275944 for background.
   "manifestTypes": {
     "internal": true,
     "channel": "stable",
@@ skipping 285 matching lines @@
     "internal": true,
     "channel": "stable",
     "dependencies": ["permission:webview"],
     "contexts": ["blessed_extension"]
   },
   "windows": {
     "dependencies": ["api:tabs"],
     "contexts": ["blessed_extension"]
   }
 }