Remove support for the "gcm_user_visible_only" manifest key.

content/public/common/manifest.cc

 // 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.
 
 #include "content/public/common/manifest.h"
 
 namespace content {
 
 const double Manifest::Icon::kDefaultDensity = 1;
 const size_t Manifest::kMaxIPCStringLength = 4 * 1024;
 
 Manifest::Icon::Icon()
     : density(kDefaultDensity) {
 }
 
 Manifest::Icon::~Icon() {
 }
 
 Manifest::RelatedApplication::RelatedApplication() {
 }
 
 Manifest::RelatedApplication::~RelatedApplication() {
 }
 
 Manifest::Manifest()
     : display(DISPLAY_MODE_UNSPECIFIED),
       orientation(blink::WebScreenOrientationLockDefault),
-      prefer_related_applications(false),
-      gcm_user_visible_only(false) {
+      prefer_related_applications(false) {
 }
 
 Manifest::~Manifest() {
 }
 
 bool Manifest::IsEmpty() const {
   return name.is_null() &&
          short_name.is_null() &&
          start_url.is_empty() &&
          display == DISPLAY_MODE_UNSPECIFIED &&
          orientation == blink::WebScreenOrientationLockDefault &&
          icons.empty() &&
          related_applications.empty() &&
          !prefer_related_applications &&
-         gcm_sender_id.is_null() &&
-         !gcm_user_visible_only;
+         gcm_sender_id.is_null();
 }
 
 } // namespace content