[Qt][WK2] Use QVariant for payload data in application URL schemes.

[Qt][WK2] Use QVariant for payload data in application URL schemes.
https://bugs.webkit.org/show_bug.cgi?id=77007

Make application schemes use QVariant for payload data.
This allows passing QByteArrays as well as simple String data.

Remove unneeded http header parts that were exposed in
QQuickNetworkReply.

Add ByteArrayTestData class to allow injecting QByteArray
data into an application scheme handler for testing.

Reviewed by Simon Hausmann.

* Shared/qt/QtNetworkReplyData.cpp:
(WebKit::QtNetworkReplyData::QtNetworkReplyData):
(WebKit::QtNetworkReplyData::encode):
(WebKit::QtNetworkReplyData::decode):
* Shared/qt/QtNetworkReplyData.h:
* UIProcess/API/qt/qquicknetworkreply.cpp:
(QQuickNetworkReply::QQuickNetworkReply):
(QQuickNetworkReply::data):
(QQuickNetworkReply::setData):
(QQuickNetworkReply::send):
* UIProcess/API/qt/qquicknetworkreply_p.h:
* UIProcess/API/qt/tests/bytearraytestdata.cpp: Added.
(ByteArrayTestData::ByteArrayTestData):
(ByteArrayTestData::latin1Data):
(ByteArrayTestData::utf8Data):
* UIProcess/API/qt/tests/bytearraytestdata.h: Added.
* UIProcess/API/qt/tests/qmltests/WebView/tst_applicationScheme.qml:
* UIProcess/API/qt/tests/qmltests/tst_qmltests.cpp:
(main):
* UIProcess/API/qt/tests/tests.pri:
* WebProcess/qt/QtNetworkReply.cpp:
(WebKit::QtNetworkReply::setReplyData):
* WebProcess/qt/QtNetworkReply.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105991 268f45cc-cd09-0410-ab3c-d52691b4dbfc