Calculate Finish time of the page load in Google Chrome programatically
Check the source code for: Chromium NetworkLogView.js
In function _updateSummaryBar() from line 710 you can view the whole process of calculating the values for the summary bar. The calculation for Finish is the following from line 773:appendChunk(Common.UIString('Finish: %s', Number.secondsToString(maxTime - baseTime)));
Whereas, maxTime is the end time of the last fulfilled requesd and baseTime is the start time of the initial request.