The execution profile for this thread in 68.0.3428.0 canary on 64-bit Windows shows that this function is taking 3.6% of non-idle runtime:
https://uma.googleplex.com/p/chrome/callstacks?sid=910aae07dc4b200cd5312719f84fd9d5

The runtime is not uniformly distributed, however. For profiles observed executing in this function the percent of time spent executing it, at every 5th percentile, is:
0,0,0,0,1,1,1,1,2,3,4,5,7,9,12,17,22,29,38,50,100

So the top 10% of profiles containing this function show 38+% of their execution time there.