Implement support for EIP-2831

[danfinlay]

Once it's ready, this provider event will notify dapps when a transaction has been cancelled or replaced:
https://eips.ethereum.org/EIPS/eip-2831

[danfinlay]

Since this would be an event that would depend on permitted/connected accounts, it might merit integrating event-awareness into rpc-cap, probably as a dependent permission.

[GregTheGreek]

I've made a few changes and revisions since early August, and I think we're add the "test it and break it" phase. For the updated spec you can find it here.

The main changes are that there are 3 transaction types now: tx_replacement (a general case), tx_speedup & tx_cancel.

I'll be tracking progress here, and will have a reference implementation made in web3.js within the next week.

[vladbat00]

Hi! Thanks for working on implementation of this EIP. I'm curious whether there are any plans to cover the following scenario:

1. User sends a transaction via a dapp
2. User disconnects the wallet (i.e. closes the app)
3. User speeds up the transaction, when the app is closed

When a user re-opens the app, will MetaMask fire the tx_replacement event about the transaction that the user speeded up when the app was closed?