[Merge] Fix appViewGuestInternal error in background pages.

extensions/common/api/_api_features.json

 // Copyright 2014 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/extensions.
 // 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 58 matching lines @@
     "dependencies": ["permission:app.window.shape"],
     "contexts": ["blessed_extension"]
   },
   // The API for the *embedder* of appview. Appview has both an embedder and
   // guest API, which are different.
   "appViewEmbedderInternal": {
     "internal": true,
     "contexts": ["blessed_extension"],
     "dependencies": ["permission:appview"]
   },
+  // Note that exposing this doesn't necessarily expose AppView,
+  // appViewEmbedderInternal is required for that.
+  // See http://crbug.com/437891.
   "appViewGuestInternal": {
     "internal": true,
-    "channel": "dev",
+    "channel": "stable",
     "contexts": ["blessed_extension"]
   },
   "bluetooth": {
     "dependencies": ["manifest:bluetooth"],
     "contexts": ["blessed_extension"]
   },
   "bluetoothLowEnergy": {
     "dependencies": ["manifest:bluetooth"],
     "contexts": ["blessed_extension"]
   },
@@ skipping 259 matching lines @@
   }],
   "webViewRequest": [{
     "dependencies": ["permission:webview"],
     "contexts": ["blessed_extension"]
   }, {
     "channel": "stable",
     "contexts": ["webui"],
     "matches": ["chrome://chrome-signin/*"]
   }]
 }