Ask HN: Would any Android phones be secure against an All Writs Act warrant?

Everyone is talking about the security of the iPhone against state-level attack. I haven't seen any discussion on how the security compares with that available on Android devices. Do any Android devices have anything comparable to the Secure Zone? I'm aware of the ARM TrustZone, but that seems to be open to vulnerabilities. What threats would the TrustZone mitigate, and is there anything more secure?