extensions: Remove chrome.webSocketProxyPrivate 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.
 
 // See c/c/e/features/* to understand this file, in particular feature.h,
 // simple_feature.h, and base_feature_provider.h.
 
 {
   "activeTab": {
     "channel": "stable",
@@ skipping 623 matching lines @@
   },
   "wallpaperPrivate": {
     "channel": "stable",
     "extension_types": ["platform_app"],
     "location": "component"
   },
   "webNavigation": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
-  "webSocketProxyPrivate": {
-    "channel": "stable",
-    "extension_types": ["extension", "packaged_app"],
-    "whitelist": [
-      "haiffjcadagjlijoggckpgfnoeiflnem",  // Citrix Receiver
-      "gnedhmakppccajfpfiihfcdlnpgomkcf",  // Citrix Receiver Beta
-      "fjcibdnjlbfnbfdjneajpipnlcppleek",  // Citrix Receiver Dev
-      "pnhechapfaindjhompbnflcldabbghjo",  // HTerm
-      "okddffdblfhhnmhodogpojmfkjmhinfp"   // HTerm dev
-    ]
-  },
   "webstorePrivate": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"],
     "whitelist": [
       "ahfgeienlihckogmohjhadlkjgocpleb",  // Web Store
       "afchcafgojfnemjkcbhfekplkmjaldaa"   // Enterprise Web Store
     ]
   },
   "webRequest": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
   "webRequestBlocking": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
   "webview": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   }
 }