The commit interval time has been hardcoded to 10 sec in the ImportantFileWriter so far. Although I've tried to find why the interval time was set to 10 sec, I failed to find it. I guess that it was set based on the empirical basis or just referred to other browsers(e.g. Mozilla).
But, embedders who use Chromium sometimes need to optimize the value. For instance, in the TV case, the users can turn off the TV suddenly or TV can be turned off due to the blackout. So it would be good if we give embedders the power to set the commit interval time.