am 2b0e6788: am ddf77b19: am b22123d1: am e41d4c04: am 0ea68954: am a5273888: am 538abc5b: am d6aeae14: Merge "Don\'t serialize required fields whose \'has\' flags are unset."

* commit '2b0e6788f9eab2271b28591383ed7db2309e69d4':