I developed a browser-deployed full-text search app in FlashBuilder which communicates RESTfully with a remote web-server. The software fits into a tiny niche--it is for use with ancient languages not modern ones, and there's no way I'm going to make any money on it but I did spend a lot of time on it.

Now that Apple won't allow Flash on the iPad, I'm looking for a 100% javascript solution and was led to consider GWT. It looked promising, but one of the apps being "showcased" as a stellar example of what can be done with GWT has this disclaimer on their website (names {removed} to protect the potentially innocent) :

Your current web browser (Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US)
 AppleWebKit/532.5 (KHTML, like Gecko) 
Chrome/4.1.249.1045 Safari/532.5) is not officially supported by 
{company and product name were here}. If you experience any problems using this site
 please install either Microsoft Internet Explorer 6+ or Mozilla Firefox 3.5+ 
before contacting {product name was here} Support.

What gives when GWT apps aren't "officially" supported on Chrome? What grade (A, B, C, D, F) would you give to GWT for cross-browser support? For folks who don't get these kinds of letter grades, A is "excellent" and "F" is failure, and "C" is average.

Thanks for your opinions.