How Star Trek IV: The Voyage Home set up Star Trek: Into Darkness

https://www.reddit.com/r/FanTheories/comments/5rhex2/how_the_star_trek_iv_the_voyage_home_set_up_star/

In the Abrams' ST reboot, a Romulan mining ship goes back in time, encounters the Kelvin with Kirk's father, and essentially wipes out the timeline of TOS. However, in "Into Darkness", we encounter Khan, who's now a lanky Brit and no longer a buff Indian with a Mexican accent. But, the disruption of the time line happened centuries after the launch of the "Botany Bay", fleeing the reprisals from the Eugenics Wars of the late 1990s.

Now, we didn't have Eugenics Wars in the 1990s, so something must have affected time to prevent them and change Khan's nationality and physique. I posit it was the crew of the Enterprise time-traveling back to the late 80s in ST4. Apparently, either somebody that McCoy saved prevented the Eugenics Wars, or that whale was going to start them.