Drop the const modifier on NotificationDisplayService::GetDisplayed

chrome/browser/notifications/native_notification_display_service.cc

 // Copyright 2016 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 "chrome/browser/notifications/native_notification_display_service.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/nullable_string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/notifications/non_persistent_notification_handler.h"
@@ skipping 62 matching lines @@
   notification_bridge_->Close(GetProfileId(profile_), notification_id);
 
   // TODO(miguelg): Figure out something better here, passing an empty
   // origin works because only non persistent notifications care about
   // this method for JS generated close calls and they don't require
   // the origin.
   handler->OnClose(profile_, "", notification_id, false /* by user */);
 }
 
 void NativeNotificationDisplayService::GetDisplayed(
-    const DisplayedNotificationsCallback& callback) const {
+    const DisplayedNotificationsCallback& callback) {
   return notification_bridge_->GetDisplayed(
       GetProfileId(profile_), profile_->IsOffTheRecord(), callback);
 }
 
 void NativeNotificationDisplayService::ProcessNotificationOperation(
     NotificationCommon::Operation operation,
     NotificationCommon::Type notification_type,
     const std::string& origin,
     const std::string& notification_id,
     int action_index,
@@ skipping 26 matching lines @@
   notification_handlers_.erase(notification_type);
 }
 
 NotificationHandler* NativeNotificationDisplayService::GetNotificationHandler(
     NotificationCommon::Type notification_type) {
   DCHECK(notification_handlers_.find(notification_type) !=
          notification_handlers_.end())
       << notification_type << " is not registered.";
   return notification_handlers_[notification_type].get();
 }