FilePicker.qml loss response after pick a file on File choose dialog

I found this bug after trying to upload a file to website,the upload plugin is written by html5,so I assume it will working properly(it's working on any modern web browser.
Pick file dialog popup just fine,but it occurred an error after select a file.
I noticed a message from qt creator console log:
QObject::connect: Incompatible sender/receiver arguments
FilePicker_QMLTYPE_55::filesSelected(QVariant) --> FilePickerController::accepted(QJSValue)
Then I found these two file that relate this issues:
1.qml/QtWebEngine/UIDelegates/FilePicker.qml
2.webengine/ui_delegates_manager.cpp
And this qt commit:
https://qt.gitorious.org/qt/qtwebengine/commit/263e54e5e777a7c45f11560398ae80161327b866#src/webengine/ui_delegates_manager.cpp
Which I thought caused this issues.
Please let me know if it's a bug or not,thank you all.
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Code:
WebEngineView

{ id: webview anchors.top:toolbar.bottom anchors.bottom: parent.bottom anchors.left:parent.left anchors.right:parent.right url: "http://www.script-tutorials.com/demos/199/index.html" }