Add layout tests for ServiceWorker's notificationclose event.

content/shell/renderer/layout_test/blink_test_runner.cc

Index: content/shell/renderer/layout_test/blink_test_runner.cc
diff --git a/content/shell/renderer/layout_test/blink_test_runner.cc b/content/shell/renderer/layout_test/blink_test_runner.cc
index b72f9813b43227972f318f95dadd3acc9d7707dd..1f6b85598893b3a87f2fc6634b81e0c3d7dccf36 100644
--- a/content/shell/renderer/layout_test/blink_test_runner.cc
+++ b/content/shell/renderer/layout_test/blink_test_runner.cc
@@ -517,6 +517,12 @@ void BlinkTestRunner::SimulateWebNotificationClick(const std::string& title,
                                                           action_index));
 }
 
+void BlinkTestRunner::SimulateWebNotificationClose(const std::string& title,
+                                                   bool by_user) {
+  Send(new LayoutTestHostMsg_SimulateWebNotificationClose(routing_id(), title,
+                                                          by_user));
+}
+
 void BlinkTestRunner::SetDeviceScaleFactor(float factor) {
   content::SetDeviceScaleFactor(render_view(), factor);
 }