Icon request: timer

A timer icon (or stopwatch) which is like clock but with buttons on the upside. Timer icon also exists on material design icons.

Compare the existing clock icon with the timer or stopwatch examples referenced in the issue, including Material Design icons. No file or test is named, so first locate where the repository stores its icon definitions and how similar icons are represented. Done means a timer icon is added in the project's existing style.

Written by the indexing model from the issue text.