Mozilla is indirectly funded by Google, yes. They don't have ownership. It's the same way that the NY Times is indirectly funded by Mazda. They pay for ads.
According to the links, the "Get Add-ons" view in Firefox uses Google Analytics to collect aggregate visitor statistics. Furthermore they note that they negotiated a special contract with Google to only collect a subset of data.
There's nothing indirect about Google cutting checks directly to Mozilla.