add user rejected errors

app/scripts/lib/message-manager.js

@@ -1,6 +1,7 @@
 const EventEmitter = require('events')
 const ObservableStore = require('obs-store')
 const ethUtil = require('ethereumjs-util')
+const { errors: rpcErrors } = require('eth-json-rpc-errors')
 const createId = require('./random-id')
 
 /**
@@ -82,7 +83,7 @@ module.exports = class MessageManager extends EventEmitter {
           case 'signed':
             return resolve(data.rawSig)
           case 'rejected':
-            return reject(new Error('MetaMask Message Signature: User denied message signature.'))
+            return reject(rpcErrors.eth.userRejectedRequest('MetaMask Message Signature: User denied message signature.'))
           default:
             return reject(new Error(`MetaMask Message Signature: Unknown problem: ${JSON.stringify(msgParams)}`))
         }

app/scripts/lib/personal-message-manager.js

@@ -1,6 +1,7 @@
 const EventEmitter = require('events')
 const ObservableStore = require('obs-store')
 const ethUtil = require('ethereumjs-util')
+const { errors: rpcErrors } = require('eth-json-rpc-errors')
 const createId = require('./random-id')
 const hexRe = /^[0-9A-Fa-f]+$/g
 const log = require('loglevel')
@@ -88,7 +89,7 @@ module.exports = class PersonalMessageManager extends EventEmitter {
           case 'signed':
             return resolve(data.rawSig)
           case 'rejected':
-            return reject(new Error('MetaMask Message Signature: User denied message signature.'))
+            return reject(rpcErrors.eth.userRejectedRequest('MetaMask Message Signature: User denied message signature.'))
           default:
             return reject(new Error(`MetaMask Message Signature: Unknown problem: ${JSON.stringify(msgParams)}`))
         }

app/scripts/lib/typed-message-manager.js

@@ -2,6 +2,7 @@ const EventEmitter = require('events')
 const ObservableStore = require('obs-store')
 const createId = require('./random-id')
 const assert = require('assert')
+const { errors: rpcErrors } = require('eth-json-rpc-errors')
 const sigUtil = require('eth-sig-util')
 const log = require('loglevel')
 const jsonschema = require('jsonschema')
@@ -78,7 +79,7 @@ module.exports = class TypedMessageManager extends EventEmitter {
           case 'signed':
             return resolve(data.rawSig)
           case 'rejected':
-            return reject(new Error('MetaMask Message Signature: User denied message signature.'))
+            return reject(rpcErrors.eth.userRejectedRequest('MetaMask Message Signature: User denied message signature.'))
           case 'errored':
             return reject(new Error(`MetaMask Message Signature: ${data.error}`))
           default:

package.json

@@ -85,7 +85,7 @@
     "eth-block-tracker": "^4.4.2",
     "eth-contract-metadata": "^1.9.2",
     "eth-ens-namehash": "^2.0.8",
-    "eth-json-rpc-errors": "^1.0.1",
+    "eth-json-rpc-errors": "^1.1.0",
     "eth-json-rpc-filters": "^4.1.0",
     "eth-json-rpc-infura": "^4.0.1",
     "eth-json-rpc-middleware": "^4.2.0",