Don't think you can call Virignia lean Democratic until we see in 2016/2020 what black turnout looks like when there is not an African-American leading the ticket.
Massive black turnout resulted in Obama winning Henrico Co in suburban Richmond by about 10 points, both in 2008 and 2012. Without a large turnout, Henrico is at best 50-50 and likely lean Republican. And in traditionally-conservative Chesterfield, also suburban Richmond, black voters really, really kept GOP margins in check. Same can be said for numerous other counties across southern Virginia and Hampton Roads.
Without black voters, Northern Virginia alone can't carry the state for Democrats, at least not yet.
It's just far from certain that another Democratic candidate will be ever again be able to motivate African-Americans anything even close to what Obama was able to.
I really don't think you can attribute Henrico to black turnout increases. While it didn't go Democratic since 48 prior to 2008 there was a rather strong Demm trend in the county for quite sometime.
Compared to national average
1988 GOP +31.57
1992 GOP +24.03
1996 GOP +21.56
2000 GOP +12.98
2004 GOP +5.66
2008 Dem +4.96
2012 Dem +8.77 (not final)
Henrico is GONE for the GOP and that was going to happen black guy or no black guy. This wasn't some one time trend here, the county was moving sharply towards the Dems well before Obama.