Remove support for the "gcm_user_visible_only" manifest key.

content/renderer/manifest/manifest_parser.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_RENDERER_MANIFEST_MANIFEST_PARSER_H_
 #define CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_
 
 #include "base/strings/nullable_string16.h"
 #include "base/strings/string_piece.h"
 #include "content/common/content_export.h"
@@ skipping 143 matching lines @@
   // https://w3c.github.io/manifest/#dfn-steps-for-processing-the-prefer_related_applications-member
   // returns true iff the field could be parsed as the boolean true.
   bool ParsePreferRelatedApplications(const base::DictionaryValue& dictionary);
 
   // Parses the 'gcm_sender_id' field of the manifest.
   // This is a proprietary extension of the Web Manifest specification.
   // Returns the parsed string if any, a null string if the parsing failed.
   base::NullableString16 ParseGCMSenderID(
       const base::DictionaryValue& dictionary);
 
-  // Parses the 'gcm_user_visible_only' field of the manifest.
-  // This is a proprietary extension of the Web Manifest specification.
-  // Returns true iff the string could be parsed as the boolean true.
-  bool ParseGCMUserVisibleOnly(const base::DictionaryValue& dictionary);
-
   const base::StringPiece& data_;
   GURL manifest_url_;
   GURL document_url_;
 
   bool failed_;
   Manifest manifest_;
   std::vector<std::string> errors_;
 
   DISALLOW_COPY_AND_ASSIGN(ManifestParser);
 };
 
 } // namespace content
 
 #endif  // CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_