Likelihood is they haven't accepted any patches, and if they have they would have been very small and minor.
Additionally, something can trivially be both open-source and non-standard and vendor specific. With the amount of Chrome specific code in Dartium, it might as well be proprietary.
Additionally, something can trivially be both open-source and non-standard and vendor specific. With the amount of Chrome specific code in Dartium, it might as well be proprietary.