Google open sources things that are not central to it's business, just like every other company out there.
MPEG-LA cannot be a patent troll let alone a known one, because it's a loose organization of companies that agree on a standard to prevent fragmentation of video and let people deal with one entity instead of a thousand. Those individual companies could be trolls.
>fights for open standards like HTML5
Really? Then this move to remove support for H.264 will get Flash even more entrenched because it would be the easiest way for content providers to get WebM video working on IE9 and Safari. Flash has already announced upcoming support for WebM.