When I visit http://www.adobe.com/software/flash/about using Google Chrome (Version 20.0.1132.47) on Mac the Flash version is reported as 11,3,300,257. However, if I visit the same page using Safari or Firefox then Flash version is reported as 11,2,202,235. So is Chrome using Flash installed in some other custom location?
Also, it's interesting that even if Chrome is using a custom Flash version, the system Flash installer still wants to stop/kill Chrome application to perform the update.