Remove support for the "gcm_user_visible_only" manifest key.

content/public/common/manifest.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_COMMON_MANIFEST_H_
 #define CONTENT_PUBLIC_COMMON_MANIFEST_H_
 
 #include <vector>
 
 #include "base/strings/nullable_string16.h"
@@ skipping 99 matching lines @@
   // A boolean that is used as a hint for the user agent to say that related
   // applications should be preferred over the web application. False if missing
   // or there is a parsing failure.
   bool prefer_related_applications;
 
   // This is a proprietary extension of the web Manifest, double-check that it
   // is okay to use this entry.
   // Null if parsing failed or the field was not present.
   base::NullableString16 gcm_sender_id;
 
-  // This is a proprietary extension of the web Manifest, double-check that it
-  // is okay to use this entry.
-  // False if parsing failed or the field was not present.
-  bool gcm_user_visible_only;
-
   // Maximum length for all the strings inside the Manifest when it is sent over
   // IPC. The renderer process should truncate the strings before sending the
   // Manifest and the browser process must do the same when receiving it.
   static const size_t kMaxIPCStringLength;
 };
 
 } // namespace content
 
 #endif // CONTENT_PUBLIC_COMMON_MANIFEST_H_