Bug 817716 - (Part 1) Add 3-dot menu to tabs panel, including a "close all tabs" option. r=bnicholson
Bug 817716 - (Part 2) Add 3-dot menu for tabs tray on tablets. r=bnicholson
Bug 1023331 - Telemetry for three-dot menu in tabs tray. r=mfinkle
Bug 1018432 - Add telemetry for "+" button in tabs tray. r=mfinkle