Add missing header in qtwebviewfunctions.

We need to include the header for QByteArray, as it's required when
calling qputenv().

Change-Id: I245d769b050525719dc6db202a6724ce887ba4a7
Reviewed-by: Yoann Lopes <yoann.lopes@theqtcompany.com>

src/webview/qtwebviewfunctions.cpp

@@ -40,6 +40,10 @@
 #include <QtWebEngine/qtwebengineglobal.h>
 #endif // QT_WEBVIEW_WEBENGINE_BACKEND
 
+#ifdef Q_OS_OSX
+#include <QtCore/qbytearray.h>
+#endif
+
 QT_BEGIN_NAMESPACE
 
 /*!