Implement WebPushProvider.unregister() in Chromium.

content/public/common/push_messaging_status.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_PUSH_MESSAGING_STATUS_H_
 #define CONTENT_PUBLIC_COMMON_PUSH_MESSAGING_STATUS_H_
 
 namespace content {
 
 // Push registration success / error codes for internal use & reporting in UMA.
@@ skipping 54 matching lines @@
   // The message was delivered, but the Service Worker passed a Promise to
   // event.waitUntil that got rejected.
   PUSH_DELIVERY_STATUS_EVENT_WAITUNTIL_REJECTED,
 
   // When making changes, update PUSH_DELIVERY_STATUS_LAST below.
 
   // Used for IPC message range checks.
   PUSH_DELIVERY_STATUS_LAST = PUSH_DELIVERY_STATUS_EVENT_WAITUNTIL_REJECTED
 };
 
+// Push unregistration success / error codes for internal use & reporting.
+enum PushUnregistrationStatus {
+  // The unregistration was successful.
+  PUSH_UNREGISTRATION_SUCCESS_UNREGISTER,
+
+  // The registration was already unregistered.
+  PUSH_UNREGISTRATION_SUCCESS_WAS_UNREGISTERED,
+
+  // The unregistration did not happen because of a network error.
+  PUSH_UNREGISTRATION_NETWORK_ERROR,
+
+  // The unregistration did not happen because of a miscellaneous error.
+  PUSH_UNREGISTRATION_UNKNOWN_ERROR,
+};
+
 const char* PushRegistrationStatusToString(PushRegistrationStatus status);
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_PUSH_MESSAGING_STATUS_H_