Take advantage of EIP 165 for App interface verification

[snario]

It seems like EIP 165 is being worked on to support one of our use cases; to verify that a particular interface is supported. For us, we'd want to verify that the reduce, resolve, and similar methods are supported on an App that is committed to in the state channel

Resources

• https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md
• https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/introspection/ERC165.sol

[shrugs]

ERC165Checker.sol is being added as part of OpenZeppelin/openzeppelin-contracts#1024 (which depends on some other issues/standards: OpenZeppelin/openzeppelin-contracts#1024 (comment) )

It'll eventually implement

using ERC165Checker for address;

// ....
require(myAddress.supportsInterface(InterfaceId_CounterfactualReducer));

Although now that I think about it, I can merge this separately and rebase Bouncer off of that, so that's what I'll do as part of OpenZeppelin/openzeppelin-contracts#1145

[snario]

@IIIIllllIIIIllllIIIIllllIIIIllllIIIIll would this be useful for #1263?