$300m a year
Still buys a lot of development resource; and from what I read Google are pretty good at churning out code. I suspect the legal budget might be signficant however - good lawyers are actually more expensive than good coders, (sadly)
If Google are spending significant amounts of money, it gives hardware makers a good reason not to fork. Even the top-tier handset companies don't have that sort of money to throw at maintaining changes in things like browser technology or payment systems or whatever is required next week in a mobile platform.
Adding another layer or removing stuff only works for so long; somebody like Amazon would struggle to compete with Google software development, so a standard Android 3.x install on a generic chinese handset will have a state of the art Chrome/WebKIt browser whereas the Amazon tablet will quickly fall behind. After all, whats the browser or twitter client like on the Kindle at the moment?
Not to mention that Google can start playing games like embedding ebook readers and access into future OS versions that Amazon will have to cut out of any bug-fix updates.
Amazon will have to struggle to stop the jail-break crowd getting an alternative Android install running on the tablet as well.
I think Google should just offer multiple Android versions - a free open source version, and a paid for version ($10 per handset or whatever) that gives hardware makers protection against patent claims. Given the amount of Android handsets, Google could make a lot of money.
Thought also occurred; Google still have plenty of money in the bank. own Motorola mobile business.. and Nokia's value is being driven down by Elop.. people assume that MS will buy Nokia once it is cheap enough.. but Google buying Nokia would be 'interesting'