This patch fixes processing of empty requests, which is necessary for successful loadFinished() signal emitting by corresponding QWebView.
No, it also happens on ubuntu 16.04 with Qt 5.5.1 - CSS images are not displayed.
Ok, we can move this to QtHelpDocumentation::setUserStyleSheet() method. Or don't fix this issue - now we lost some small images like arrows, not so critical.
Original offline.css contains 10 (for Qt 5.7.0) wrong lines with relative paths for images. I think it not right to add all such fixes into setUserStyleSheet() method. Therefore we have such variants:
What are you think about it?