feat: UtilityProcess API (#34980)

* chore: initial scaffolding

* chore: implement interface and docs

* chore: address code style review

* fix: cleanup of utility process on shutdown

* chore: simplify NodeBindings::CreateEnvironment

* chore: rename disableLibraryValidation => allowLoadingUnsignedLibraries

* chore: implement process.parentPort

* chore(posix): implement stdio pipe interface

* chore(win): implement stdio interface

* chore: reenable SetNodeOptions for utility process

* chore: add specs

* chore: fix lint

* fix: update kill API

* fix: update process.parentPort API

* fix: exit event

* docs: update exit event

* fix: tests on linux

* chore: expand on some comments

* fix: shutdown of pipe reader

Avoid logging since it is always the case that reader end of
pipe will terminate after the child process.

* fix: remove exit code check for crash spec

* fix: rm PR_SET_NO_NEW_PRIVS for unsandbox utility process

* chore: fix incorrect rebase

* fix: address review feedback

* chore: rename utility_process -> utility

* chore: update docs

* chore: cleanup c++ implemantation

* fix: leak in NodeServiceHost impl

* chore: minor cleanup

* chore: cleanup JS implementation

* chore: flip default stdio to inherit

* fix: some api improvements

* Support cwd option
* Remove path restriction for modulePath
* Rewire impl for env support

* fix: add tests for cwd and env option

* chore: alt impl for reading stdio handles

* chore: support message queuing

* chore: fix lint

* chore: new UtilityProcess => utilityProcess.fork

* fix: support for uncaught exception exits

* chore: remove process.execArgv as default

* fix: windows build

* fix: style changes

* fix: docs and style changes

* chore: update patches

* spec: disable flaky test on win32 arm CI

Co-authored-by: PatchUp <73610968+patchup[bot]@users.noreply.github.com>

docs/api/parent-port.md

@@ -0,0 +1,46 @@
+# parentPort
+
+> Interface for communication with parent process.
+
+Process: [Utility](../glossary.md#utility-process)
+
+`parentPort` is an [EventEmitter][event-emitter].
+_This object is not exported from the `'electron'` module. It is only available as a property of the process object in the Electron API._
+
+```js
+// Main process
+const child = utilityProcess.fork(path.join(__dirname, 'test.js'))
+child.postMessage({ message: 'hello' })
+child.on('message', (data) => {
+  console.log(data) // hello world!
+})
+
+// Child process
+process.parentPort.on('message', (e) => {
+  process.parentPort.postMessage(`${e.data} world!`)
+})
+```
+
+## Events
+
+The `parentPort` object emits the following events:
+
+### Event: 'message'
+
+Returns:
+
+* `messageEvent` Object
+  * `data` any
+  * `ports` MessagePortMain[]
+
+Emitted when the process receives a message. Messages received on
+this port will be queued up until a handler is registered for this
+event.
+
+## Methods
+
+### `parentPort.postMessage(message)`
+
+* `message` any
+
+Sends a message from the process to its parent.

docs/api/process.md

@@ -113,6 +113,7 @@ A `string` representing the current process's type, can be:
 * `browser` - The main process
 * `renderer` - A renderer process
 * `worker` - In a web worker
+* `utility` - In a node process launched as a service
 
 ### `process.versions.chrome` _Readonly_
 
@@ -134,6 +135,11 @@ Each frame has its own JavaScript context. When contextIsolation is enabled, the
 world also has a separate JavaScript context.
 This property is only available in the renderer process.
 
+### `process.parentPort`
+
+A [`Electron.ParentPort`](parent-port.md) property if this is a [`UtilityProcess`](utility-process.md)
+(or `null` otherwise) allowing communication with the parent process.
+
 ## Methods
 
 The `process` object has the following methods:

docs/api/utility-process.md

@@ -0,0 +1,136 @@
+# utilityProcess
+
+`utilityProcess` creates a child process with
+Node.js and Message ports enabled. It provides the equivalent of [`child_process.fork`][] API from Node.js
+but instead uses [Services API][] from Chromium to launch the child process.
+
+Process: [Main](../glossary.md#main-process)<br />
+
+## Methods
+
+### `utilityProcess.fork(modulePath[, args][, options])`
+
+* `modulePath` string - Path to the script that should run as entrypoint in the child process.
+* `args` string[] (optional) - List of string arguments that will be available as `process.argv`
+  in the child process.
+* `options` Object (optional)
+  * `env` Object (optional) - Environment key-value pairs. Default is `process.env`.
+  * `execArgv` string[] (optional) - List of string arguments passed to the executable.
+  * `cwd` string (optional) - Current working directory of the child process.
+  * `stdio` (string[] | string) (optional) - Allows configuring the mode for `stdout` and `stderr`
+    of the child process. Default is `inherit`.
+    String value can be one of `pipe`, `ignore`, `inherit`, for more details on these values you can refer to
+    [stdio][] documentation from Node.js. Currently this option only supports configuring `stdout` and
+    `stderr` to either `pipe`, `inherit` or `ignore`. Configuring `stdin` is not supported; `stdin` will
+    always be ignored.
+    For example, the supported values will be processed as following:
+    * `pipe`: equivalent to ['ignore', 'pipe', 'pipe'] (the default)
+    * `ignore`: equivalent to 'ignore', 'ignore', 'ignore']
+    * `inherit`: equivalent to ['ignore', 'inherit', 'inherit']
+  * `serviceName` string (optional) - Name of the process that will appear in `name` property of
+    [`child-process-gone` event of `app`](app.md#event-child-process-gone).
+    Default is `node.mojom.NodeService`.
+  * `allowLoadingUnsignedLibraries` boolean (optional) _macOS_ - With this flag, the utility process will be
+    launched via the `Electron Helper (Plugin).app` helper executable on macOS, which can be
+    codesigned with `com.apple.security.cs.disable-library-validation` and
+    `com.apple.security.cs.allow-unsigned-executable-memory` entitlements. This will allow the utility process
+    to load unsigned libraries. Unless you specifically need this capability, it is best to leave this disabled.
+    Default is `false`.
+
+Returns [`UtilityProcess`](utility-process.md#class-utilityprocess)
+
+## Class: UtilityProcess
+
+> Instances of the `UtilityProcess` represent the Chromium spawned child process
+> with Node.js integration.
+
+`UtilityProcess` is an [EventEmitter][event-emitter].
+
+### Instance Methods
+
+#### `child.postMessage(message, [transfer])`
+
+* `message` any
+* `transfer` MessagePortMain[] (optional)
+
+Send a message to the child process, optionally transferring ownership of
+zero or more [`MessagePortMain`][] objects.
+
+For example:
+
+```js
+// Main process
+const { port1, port2 } = new MessageChannelMain()
+const child = utilityProcess.fork(path.join(__dirname, 'test.js'))
+child.postMessage({ message: 'hello' }, [port1])
+
+// Child process
+process.parentPort.once('message', (e) => {
+  const [port] = e.ports
+  // ...
+})
+```
+
+#### `child.kill()`
+
+Returns `boolean`
+
+Terminates the process gracefully. On POSIX, it uses SIGTERM
+but will ensure the process is reaped on exit. This function returns
+true if the kill is successful, and false otherwise.
+
+### Instance Properties
+
+#### `child.pid`
+
+A `Integer | undefined` representing the process identifier (PID) of the child process.
+If the child process fails to spawn due to errors, then the value is `undefined`. When
+the child process exits, then the value is `undefined` after the `exit` event is emitted.
+
+#### `child.stdout`
+
+A `NodeJS.ReadableStream | null` that represents the child process's stdout.
+If the child was spawned with options.stdio[1] set to anything other than 'pipe', then this will be `null`.
+When the child process exits, then the value is `null` after the `exit` event is emitted.
+
+```js
+// Main process
+const { port1, port2 } = new MessageChannelMain()
+const child = utilityProcess.fork(path.join(__dirname, 'test.js'))
+child.stdout.on('data', (data) => {
+  console.log(`Received chunk ${data}`)
+})
+```
+
+#### `child.stderr`
+
+A `NodeJS.ReadableStream | null` that represents the child process's stderr.
+If the child was spawned with options.stdio[2] set to anything other than 'pipe', then this will be `null`.
+When the child process exits, then the value is `null` after the `exit` event is emitted.
+
+### Instance Events
+
+#### Event: 'spawn'
+
+Emitted once the child process has spawned successfully.
+
+#### Event: 'exit'
+
+Returns:
+
+* `code` number - Contains the exit code for
+the process obtained from waitpid on posix, or GetExitCodeProcess on windows.
+
+Emitted after the child process ends.
+
+#### Event: 'message'
+
+Returns:
+
+* `message` any
+
+Emitted when the child process sends a message using [`process.parentPort.postMessage()`](process.md#processparentport).
+
+[`child_process.fork`]: https://nodejs.org/dist/latest-v16.x/docs/api/child_process.html#child_processforkmodulepath-args-options
+[Services API]: https://chromium.googlesource.com/chromium/src/+/master/docs/mojo_and_services.md
+[stdio]: https://nodejs.org/dist/latest/docs/api/child_process.html#optionsstdio