Remove support for the "gcm_user_visible_only" manifest key.

content/renderer/manifest/manifest_parser.cc

Index: content/renderer/manifest/manifest_parser.cc
diff --git a/content/renderer/manifest/manifest_parser.cc b/content/renderer/manifest/manifest_parser.cc
index 924d2aa9668581ef09e52d8e38378dd45423f3b0..02a5c9c5bedf461464ffc68ee4fba7c45ca20170 100644
--- a/content/renderer/manifest/manifest_parser.cc
+++ b/content/renderer/manifest/manifest_parser.cc
@@ -130,7 +130,6 @@ void ManifestParser::Parse() {
   manifest_.prefer_related_applications =
       ParsePreferRelatedApplications(*dictionary);
   manifest_.gcm_sender_id = ParseGCMSenderID(*dictionary);
-  manifest_.gcm_user_visible_only = ParseGCMUserVisibleOnly(*dictionary);
 
   ManifestUmaUtil::ParseSucceeded(manifest_);
 }
@@ -409,9 +408,4 @@ base::NullableString16 ManifestParser::ParseGCMSenderID(
   return ParseString(dictionary, "gcm_sender_id", Trim);
 }
 
-bool ManifestParser::ParseGCMUserVisibleOnly(
-    const base::DictionaryValue& dictionary) {
-  return ParseBoolean(dictionary, "gcm_user_visible_only", false);
-}
-
 } // namespace content