You're building a new OS based on the Linux kernel + Chrome Browser, which is cool because these are both high-quality Free Software projects. But then you wander off and sidle up to Adobe instead of working with Free Software such as Gnash.
Gnash is all fine and good, except that it's a piece of shit and doesn't work. Just like open-source Java.
Look, I like open source as much as the next guy (more, probably), but more than anything I like working software. Google can either spend lots of man-hours making Gnash work properly with all the Flash out there on the web today, and then spend more man-hours keeping it up-to-date as Adobe adds new features that various popular websites take advantage of, or they can just partner with Adobe and use real Flash, spending just a few man-hours to integrate it into their system. Google is a business, and while they may make some choices ideologically, in most cases they need to use the best tool for the job. In this case, that tool is Flash.