Sandbox: explore how to support direct helper process to renderer communication

[bpasero]

Allow direct communication between a helper process and the renderer.

Some raw ideas

• what if Electron would provide an API similar to BrowserWindow.loadUrl but UtilityProcess.loadUrl to create such a child process
• Electron should delegate this to Chrome and reuse the ability Chrome has to spawn utility processes like GPU and Network
• Utility process has node.js integration enabled and direct communication support to a renderer (either via electron IPC or message ports)

[Tyriar]

@deepak1556 any update on this? Do we have an upstream issue we can link?