There has been as significant increase in load time from Chrome 64 to Chrome 65 in our WebGL app developed with Unity. This can easily be reproduced by testing and comparing between Chrome 64 and 65. Please note that the time to enter a game has increased in Chrome 65. 

Link to our web app:
http://www.kogama.com/games/play/2593313/

We have also reproduced this in the official Unity WebGL demo: 
https://beta.unity3d.com/jonas/AngryBots/

AngryBots went from 7.324 seconds load time in chrome 64 to 10.274 seconds in Chrome Beta 65.

64: https://aboutmybrowser.com/1NJ-bYo3
65: https://aboutmybrowser.com/88BduEax

Running Windows 10 64 bit
Intel HD Graphics 630
Intel i7-7700
16GB Ram