Add NotificationOptions.actions so websites can provide buttons (blink)

public/platform/modules/notifications/WebNotificationAction.h

Index: public/platform/modules/notifications/WebNotificationAction.h
diff --git a/public/platform/modules/notifications/WebNotificationAction.h b/public/platform/modules/notifications/WebNotificationAction.h
new file mode 100644
index 0000000000000000000000000000000000000000..4516b8c218615297b9c2bac5bdbce9343285e49e
--- /dev/null
+++ b/public/platform/modules/notifications/WebNotificationAction.h
@@ -0,0 +1,28 @@
+// Copyright 2015 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 WebNotificationAction_h
+#define WebNotificationAction_h
+
+#include "public/platform/WebString.h"
+
+namespace blink {
+
+// Structure representing the data associated with a Web Notification action.
+struct WebNotificationAction {
+    // Empty and copy constructor only for WebVector.
+    WebNotificationAction() = default;
+    WebNotificationAction(const WebNotificationAction&) = default;
+
+    WebNotificationAction(const WebString& title)
+        : title(title)
+    {
+    }
+
+    WebString title;
+};
+
+} // namespace blink
+
+#endif // WebNotificationAction_h