Zygote : Block SIGCHLD during fork. am: b1f1209d9a am: 35b8453338 am: 14bd75fa79 am: 50b0c3be57  -s ours am: e1e735bcb9 am: 072b70bae3 am: ba6d5ee377 am: f3f784853d am: 8ea47824fa am: 2f2611636b am: 86e1929551 am: 8ecbb2b2ae
am: 5db2340ba2

Change-Id: I6ce389eb25162f90dc39a3f023ee7f35eccfcfe4