The "MetaMask middleware" is the set of middleware for handling methods that
we don't send to the network. This includes signing, encryption, `getAccounts`,
and methods that rely on pending transaction state.
Previously this middleware was setup as part of the network client, despite
having nothing to do with the network. They have been moved into the main RPC
pipeline established in `metamask-controller.js` instead.
This is a pure refactor, and should have no functional changes. The middleware
are still run in exactly the same order with the same arguments.
Our middleware for handling subscription and filter-related methods (`eth-json-rpc-filters`) currently lives in our RPC pipeline ahead of the network stack. This commit moves this middleware to the network client middleware instead. There are two reasons for this change. First, this middleware wraps RPC methods that are supported by the network. Second, it is necessary for this middleware to live with the network client so that it will aid us in unifying the NetworkController in this repo and the NetworkController in the `controllers` repo.
Co-authored-by: Elliot Winkler <elliot.winkler@gmail.com>
The network controller module has been renamed from `network.js` to
`network-controller.js`. All of our newer controllers have "controller"
in the module names, so this aligns better with that convention. It
also brings the test module name into alignment (it's already called
"network-controller.test.js").
