Implement WebPushProvider.unregister() in Chromium.

content/shell/browser/layout_test/layout_test_push_messaging_service.cc

Index: content/shell/browser/layout_test/layout_test_push_messaging_service.cc
diff --git a/content/shell/browser/layout_test/layout_test_push_messaging_service.cc b/content/shell/browser/layout_test/layout_test_push_messaging_service.cc
index e6639c3bd68c41edd1a33adc884ac553f892a306..b8240e5acb0a9b2368d044d84f387c3ad198db86 100644
--- a/content/shell/browser/layout_test/layout_test_push_messaging_service.cc
+++ b/content/shell/browser/layout_test/layout_test_push_messaging_service.cc
@@ -22,6 +22,7 @@ void LayoutTestPushMessagingService::SetPermission(const GURL& origin,
 
 void LayoutTestPushMessagingService::ClearPermissions() {
   permission_map_.clear();
+  registrations_.clear();
 }
 
 GURL LayoutTestPushMessagingService::GetPushEndpoint() {
@@ -47,6 +48,7 @@ void LayoutTestPushMessagingService::RegisterFromWorker(
     const PushMessagingService::RegisterCallback& callback) {
   if (GetPermissionStatus(requesting_origin, requesting_origin) ==
       blink::WebPushPermissionStatusGranted) {
+    registrations_.insert(requesting_origin);
     callback.Run("layoutTestRegistrationId",
                  PUSH_REGISTRATION_STATUS_SUCCESS_FROM_PUSH_SERVICE);
   } else {
@@ -72,4 +74,11 @@ LayoutTestPushMessagingService::GetPermissionStatus(
   return it->second;
 }
 
+void LayoutTestPushMessagingService::Unregister(
+    const GURL& requesting_origin,
+    int64 service_worker_registration_id,
+    const UnregisterCallback& callback) {
+  callback.Run(registrations_.erase(requesting_origin) == 1);
+}
+
 }  // namespace content