Move topSites API out of experimental

chrome/common/extensions/api/_permission_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.
 
 {
   "appNotifications": {
     "extension_types": ["packaged_app", "hosted_app"]
   },
   "background": {
     "extension_types": [
@@ skipping 132 matching lines @@
   "tabs": {
     "extension_types": ["extension", "packaged_app"]
   },
   "terminalPrivate": {
     "extension_types": ["extension", "packaged_app", "platform_app"],
     "whitelist": [
       "pnhechapfaindjhompbnflcldabbghjo",  // HTerm
       "okddffdblfhhnmhodogpojmfkjmhinfp"   // HTerm dev
     ]
   },
+  "topSites": {
+    "extension_types": ["extension", "packaged_app", "platform_app"]
+  },
   "tts": {
     "extension_types": ["extension", "packaged_app", "platform_app"]
   },
   "ttsEngine": {
     "extension_types": ["extension", "packaged_app", "platform_app"]
   },
   "unlimitedStorage": {
     "extension_types": [
       "extension", "packaged_app", "hosted_app", "platform_app"
     ]
@@ skipping 18 matching lines @@
       "afchcafgojfnemjkcbhfekplkmjaldaa"   // Enterprise Web Store
     ]
   },
   "webRequest": {
     "extension_types": ["extension", "packaged_app"]
   },
   "webRequestBlocking": {
     "extension_types": ["extension", "packaged_app"]
   }
 }