preferences - introduce preferences controller

app/scripts/lib/controllers/preferences.js

@@ -0,0 +1,30 @@
+const ObservableStore = require('obs-store')
+const normalizeAddress = require('../sig-util').normalize
+
+class PreferencesController {
+
+  constructor (opts = {}) {
+    const initState = opts.initState || {}
+    this.store = new ObservableStore(initState)
+  }
+
+  //
+  // PUBLIC METHODS
+  //
+
+  setSelectedAddress(_address) {
+    const address = normalizeAddress(_address)
+    this.store.updateState({ selectedAddress: address })
+  }
+
+  getSelectedAddress(_address) {
+    return this.store.getState().selectedAddress
+  }
+
+  //
+  // PRIVATE METHODS
+  //
+
+}
+
+module.exports = PreferencesController

app/scripts/metamask-controller.js

@@ -11,6 +11,7 @@ const streamIntoProvider = require('web3-stream-provider/handler')
 const MetaMaskProvider = require('web3-provider-engine/zero.js')
 const setupMultiplex = require('./lib/stream-utils.js').setupMultiplex
 const KeyringController = require('./keyring-controller')
+const PreferencesController = require('./lib/controllers/preferences')
 const NoticeController = require('./notice-controller')
 const messageManager = require('./lib/message-manager')
 const TxManager = require('./transaction-manager')
@@ -40,6 +41,11 @@ module.exports = class MetamaskController extends EventEmitter {
     })
     this.configManager.updateConversionRate()
 
+    // preferences controller
+    this.prefencesController = new PreferencesController({
+      initState: initState.PrefencesController,
+    })
+
     // rpc provider
     this.provider = this.initializeProvider(opts)
     this.provider.on('block', this.logBlock.bind(this))
@@ -101,6 +107,9 @@ module.exports = class MetamaskController extends EventEmitter {
     this.keyringController.store.subscribe((state) => {
       this.store.updateState({ KeyringController: state })
     })
+    this.prefencesController.store.subscribe((state) => {
+      this.store.updateState({ PrefencesController: state })
+    })
   }
 
   //