feat: add TextField and Button APIs

[zcbenz]

None of the APIs are expected to be stable, and they are hidden under enable_view_api build flag.

An example creating a minimal browser:

const {app, webContents, LabelButton, BoxLayout, TopLevelWindow, TextField, View, WebContentsView} = require('electron')

let win = null
app.once('ready', () => {
  const contentView = new View()
  const contentLayout = new BoxLayout('vertical')
  contentView.setLayoutManager(contentLayout)

  const toolbar = new View()
  const toolbarLayout = new BoxLayout('horizontal')
  toolbar.setLayoutManager(toolbarLayout)
  contentView.addChildView(toolbar)

  const addressBar = new TextField()
  toolbar.addChildView(addressBar)
  toolbarLayout.setFlexForView(addressBar, 1)

  const go = new LabelButton('GO')
  toolbar.addChildView(go)

  const web = webContents.create({})
  const webview = new WebContentsView(web)
  contentView.addChildView(webview)
  contentLayout.setFlexForView(webview, 1)

  win = new TopLevelWindow()
  win.setContentView(contentView)

  go.on('click', () => web.loadURL(addressBar.getText()))
  web.on('navigation-entry-commited', (event, url) => addressBar.setText(url))
  web.loadURL('http://github.com')
})

[MarshallOfSound]

Should these components live in a separate place to api. Like maybe it should be used through require('electron').UI.Button and require('electron').UI.TextField Etc.

Just so there is a logical and physical separation between API and UI stuff 👍

This is looking super cool

[ckerr]

👍 on both of @MarshallOfSound's points: might be good to have a separate namespace, and this looks super cool

[zcbenz]

Should these components live in a separate place to api. Like maybe it should be used through require('electron').UI.Button and require('electron').UI.TextField Etc.

👍 , will do it in another pull request.

[eveningkid]

@zcbenz is there any way to try this out?
It looks really promising. Makes me think of your side-project! :)