glGraphRetime

Very Important :
tool visually updates only after mouse over the graphEditor

put file glGraphRetime.py to maya scripts folder
run script command from file
graphRetime_runCommand.py
run in python tab, assign it on hotKey or shelf 

here actual run script command:
import glGraphRetime;glGraphRetime.runCommand(kp=(10,10))

kp=(10,10)  it's mean if do not have selected timeRange
it will create bars 10 frames before and 10 frames after current frame