Bug 1034331 - Decrement fxa step count when going back from COPPA screen to enter email screen. r=ferjm

    Also: only increment the fxa step count if moving forward in the flow.
Merge pull request #21506 from 6a68/bug-1034331-fxa-coppa-progress-bar

Bug 1034331 - Decrement fxa step count when going back from COPPA screen...