Return a Promise from showAccountDetail thunk (#8427)

`showAccountDetail` returned a thunk that didn't return a Promise,
despite doing async work. Now it returns a Promise.

This action is only called in one place, and it looks like the actions
dispatched alongside it were meant to be run in parallel, so no changes
were made there.

test/unit/ui/app/actions.spec.js

@@ -985,33 +985,30 @@ describe('Actions', function () {
   describe('#showAccountDetail', function () {
     let setSelectedAddressSpy
 
-    beforeEach(function () {
-      setSelectedAddressSpy = sinon.stub(background, 'setSelectedAddress')
-    })
-
     afterEach(function () {
       setSelectedAddressSpy.restore()
     })
 
-    it('#showAccountDetail', function () {
+    it('#showAccountDetail', async function () {
+      setSelectedAddressSpy = sinon.stub(background, 'setSelectedAddress')
+        .callsArgWith(1, null)
       const store = mockStore()
 
-      store.dispatch(actions.showAccountDetail())
+      await store.dispatch(actions.showAccountDetail())
       assert(setSelectedAddressSpy.calledOnce)
     })
 
-    it('displays warning if setSelectedAddress throws', function () {
+    it('displays warning if setSelectedAddress throws', async function () {
+      setSelectedAddressSpy = sinon.stub(background, 'setSelectedAddress')
+        .callsArgWith(1, new Error('error'))
       const store = mockStore()
       const expectedActions = [
         { type: 'SHOW_LOADING_INDICATION', value: undefined },
         { type: 'HIDE_LOADING_INDICATION' },
         { type: 'DISPLAY_WARNING', value: 'error' },
       ]
-      setSelectedAddressSpy.callsFake((_, callback) => {
-        callback(new Error('error'))
-      })
 
-      store.dispatch(actions.showAccountDetail())
+      await store.dispatch(actions.showAccountDetail())
       assert.deepEqual(store.getActions(), expectedActions)
     })
   })

ui/app/store/actions.js

@@ -1191,21 +1191,25 @@ export function setSelectedAddress (address) {
 }
 
 export function showAccountDetail (address) {
-  return (dispatch) => {
+  return async (dispatch) => {
     dispatch(showLoadingIndication())
     log.debug(`background.setSelectedAddress`)
-    background.setSelectedAddress(address, (err, tokens) => {
+
+    let tokens
+    try {
+      tokens = await promisifiedBackground.setSelectedAddress(address)
+    } catch (error) {
       dispatch(hideLoadingIndication())
-      if (err) {
-        return dispatch(displayWarning(err.message))
-      }
-      dispatch(updateTokens(tokens))
-      dispatch({
-        type: actionConstants.SHOW_ACCOUNT_DETAIL,
-        value: address,
-      })
-      dispatch(setSelectedToken())
+      dispatch(displayWarning(error.message))
+      return
+    }
+    dispatch(hideLoadingIndication())
+    dispatch(updateTokens(tokens))
+    dispatch({
+      type: actionConstants.SHOW_ACCOUNT_DETAIL,
+      value: address,
     })
+    dispatch(setSelectedToken())
   }
 }