Removing chrome.pushMessaging API

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.
 
 // This features file defines permissions for 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.
 
 // To add a new whitelisted ID, SHA-1 it and force it to uppercase. In Bash:
@@ skipping 783 matching lines @@
       "DF84F03F9B960409CCDE0D895B9650EBE81C0A8E",  // Hangout Services
       "80B9DC58E5210749F052F5B4DB239C50CF72AEB6",  // Hangouts test extension
       "7D7A4B147FE39908A5AF13F85E38989C54BBE41C",  // http://crbug.com/370700
       "0EEDFC0EED87871237213F34EBC7B4982A195C95"   // http://crbug.com/370700
     ]
   }],
   "proxy": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app"]
   },
-  "pushMessaging": {
-    "channel": "stable",
-    "extension_types": ["extension", "platform_app"]
-  },
   "imageWriterPrivate": {
     "channel": "stable",
     "extension_types": ["platform_app"],
     "whitelist": [
       "A291B26E088FA6BA53FFD72F0916F06EBA7C585A", // http://crbug.com/329088
       "D7986543275120831B39EF28D1327552FC343960", // http://crbug.com/329088
       "BCC85C0D7F85897F2699974421EA402144C35C0C"  // API Test
     ]
   },
   "inlineInstallPrivate":
@@ skipping 146 matching lines @@
   },
   "webstorePrivate": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app", "hosted_app"],
     "whitelist": [
       "B44D08FD98F1523ED5837D78D0A606EA9D6206E5",  // Web Store
       "2653F6F6C39BC6EEBD36A09AFB92A19782FF7EB4"   // Enterprise Web Store
     ]
   }
 }