Remove Chromecast extension support from cast system tray menu.

chrome/common/extensions/api/_api_features.json

 // Copyright 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 chrome/common/extensions/api/_features.md to understand this file, as
 // well as 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 163 matching lines @@
       "A4577D8C2AF4CF26F40CBCA83FFA4251D6F6C8F8",  // http://crbug.com/497301
       "A8208CCC87F8261AFAEB6B85D5E8D47372DDEA6B",  // http://crbug.com/497301
       "EFCF5358672FEE04789FD2EC3638A67ADEDB6C8C"   // http://crbug.com/514696
     ],
     "contexts": ["blessed_extension"]
   }],
   "browsingData": {
     "dependencies": ["permission:browsingData"],
     "contexts": ["blessed_extension"]
   },
   "cast.channel": {

[Devlin, 2016/11/05 06:31:34]

To confirm, we still need all the rest of these?

[jdufault, 2016/11/08 20:15:59]

I'll reach out to the owners and see if we can remove it in a separate CL.

     "dependencies": ["permission:cast"],
     "contexts": ["blessed_extension"]
   },
-  "cast.devicesPrivate": {
-    "dependencies": ["permission:cast"],
-    "contexts": ["blessed_extension"],
-    "platforms": ["chromeos"]
-  },
   "cast.streaming.rtpStream": {
     "dependencies": ["permission:cast.streaming"],
     "contexts": ["blessed_extension"]
   },
   "cast.streaming.receiverSession": {
     "dependencies": ["permission:cast.streaming"],
     "contexts": ["blessed_extension"]
   },
   "cast.streaming.session": {
     "dependencies": ["permission:cast.streaming"],
@@ skipping 621 matching lines @@
     "internal": true,
     "channel": "stable",
     "dependencies": ["permission:webview"],
     "contexts": ["blessed_extension"]
   },
   "windows": {
     "dependencies": ["api:tabs"],
     "contexts": ["blessed_extension"]
   }
 }