For historical reasons we have a lot of duplication of code between WebEngineWidgets and WebEngine (QML) modules. We should aim for sharing more code through WebEngineCore, ideally by moving to public classes in QWebEngineCore

Just by looking at the class names, following classes are obvious candidates for unification

• QWebEngineProfile, QQuickWebEngineProfile
• QWebEngineCertificateError, QQuickWebEngineCertificateError
• QWebEngineDownloadItem, QQuickWebEngineDownloadItem
• QWebEngineFullScreenRequest, QQuickWebEngineFullScreenRequest
• QWebEngineHistory, QQuickWebEngineHistory
• QWebEngineScript, QQuickWebEngineScript
• QWebEngineSettings, QQUickWebEngineSettings
• QWebEngineView, QQuickWebEngineView