Sweet Jesus, another one?
WTF is up with Google lately - Dart, WebP and (to a lesser extent) SPDY are all Chocolate Factory inventions to "improve" the web, but they're all single-vendor solutions designed to usurp existing multi-vendor ones. If successful they'll drag the web back to the bad old days.
(Incidentally the fact they're open source doesn't matter a damn. I could open source my own image format tomorrow, but that doesn't mean I should expect Mozilla and MS to implement it).
The more powerful a company becomes, the more it ignores the very standards that helped it grow. Same as it ever was.