Add support for gcm_sender_id in Manifest.

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 "base/strings/nullable_string16.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
@@ skipping 13 matching lines @@
 
   // Null if the parsing failed or the field was not present.
   base::NullableString16 name;
 
   // Null if the parsing failed or the field was not present.
   base::NullableString16 short_name;
 
   // Empty if the parsing failed or the field was not present.
   GURL start_url;
 
+  // This is an extension only used when PushMessaging Blink flag is enabled.
+  // Null if parsing failed or the field was not present.
+  base::NullableString16 gcm_sender_id;
+
   // 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_