Do not reload the full page on disconnects

When hopping between networks (system sleep/resume or unreliable wireless networks), or when the master is restarted, the whole page is reloaded. This loses the view state (scrolling position in a log file) and wastes data (requirement to download a full log file) and is not great for usability.

I guess that this hack was added in commit a7031b2e66daee2a4e82954efc62f823c39cd7af (merged in https://github.com/buildbot/buildbot/pull/2111), but what are the exact requirements that need to be satisfied for this hack to be removed? What pages is this relevant for?