To use without "https://www.googleapis.com/auth/drive.metadata.readonly" scope, open Google Doc, open Chrome Developer Tools, open Network Panel, click on see revision history, look for xhr request that matches the one below, modify to remove start and end parameters. Upload the json.txt file to timecard to generate a Gantt chart of time spent in the Google Doc.

Uses unofficial revisions: tiles API to get detailed revision history data.
https://docs.google.com/document/d/{ID}/revisions/tiles?id={ID}&start=1&end={END}&showDetailedRevisions=true&filterNamed=false&token={TOKEN}&includes_info_params=true

To future Steven, sorry in advance, the code is spagetti, this entire thing was written in less than 7 hours.