Code review comment for lp:~zaspire/oxide/lp_1259219

Ooh, one other thing I forgot to mention :)

Moving oxide::WebView::web_contents_ results in our reference to its BrowserContext being released before the WebContents is deleted, which results in a use-after-free. There did used to be a comment stating that the order of these members shouldn't be changed, but that seems to have disappeared at some point