[WIP] Implement sound attr in notification

public/platform/modules/notifications/WebNotificationData.h

Index: public/platform/modules/notifications/WebNotificationData.h
diff --git a/public/platform/modules/notifications/WebNotificationData.h b/public/platform/modules/notifications/WebNotificationData.h
index 75b2575bc93323c4a40354845645166bae443c01..4c6e107c5f26f8a9fa9b7b4cfe40df584a82151e 100644
--- a/public/platform/modules/notifications/WebNotificationData.h
+++ b/public/platform/modules/notifications/WebNotificationData.h
@@ -24,13 +24,14 @@ struct WebNotificationData {
     {
     }
 
-    WebNotificationData(const WebString& title, Direction direction, const WebString& lang, const WebString& body, const WebString& tag, const WebURL& icon, const WebVector<int>& vibrate, bool silent, const WebVector<char>& data)
+    WebNotificationData(const WebString& title, Direction direction, const WebString& lang, const WebString& body, const WebString& tag, const WebURL& icon, const WebURL& sound, const WebVector<int>& vibrate, bool silent, const WebVector<char>& data)
         : title(title)
         , direction(direction)
         , lang(lang)
         , body(body)
         , tag(tag)
         , icon(icon)
+        , sound(sound)
         , vibrate(vibrate)
         , silent(silent)
         , data(data)
@@ -43,6 +44,7 @@ struct WebNotificationData {
     WebString body;
     WebString tag;
     WebURL icon;
+    WebURL sound;
     WebVector<int> vibrate;
     bool silent;
     WebVector<char> data;