For example, Google uses ISO-8859-1 encoding. This patch allows us to
decode such responses, falling back to UTF-8 if a Content-Type was not
specified or could not be parsed. We should also now handle if decoding
fails, rather than crashing inside JsonParser.
This implements an autocomplete engine inside LibWebView, to replace the
engine currently used by Qt. Whereas Qt uses the Qt Network framework to
perform autocomplete requests, LibWebView uses RequestServer. This moves
downloading this untrusted data out of the browser process.
This patch only implements the persisted settings and their UI. It does
not integrate this engine into the browser UI.
