feat: add process.contextId used by @electron/remote

docs/api/process.md

@@ -35,6 +35,7 @@ In sandboxed renderers the `process` object contains only a subset of the APIs:
 * `versions`
 * `mas`
 * `windowsStore`
+* `contextId`
 
 ## Events
 
@@ -133,6 +134,11 @@ A `String` representing Electron's version string.
 A `Boolean`. If the app is running as a Windows Store app (appx), this property is `true`,
 for otherwise it is `undefined`.
 
+### `process.versions.contextId` _Readonly_
+
+A `String` (optional) representing unique ID of the current JavaScript context.
+This property is only available in the renderer process.
+
 ## Methods
 
 The `process` object has the following methods:

lib/renderer/init.ts

@@ -39,6 +39,9 @@ require('@electron/internal/common/init');
 // The global variable will be used by ipc for event dispatching
 const v8Util = process._linkedBinding('electron_common_v8_util');
 
+const contextId = v8Util.getHiddenValue<string>(global, 'contextId');
+Object.defineProperty(process, 'contextId', { get: () => contextId });
+
 const { ipcRendererInternal } = require('@electron/internal/renderer/ipc-renderer-internal');
 const ipcRenderer = require('@electron/internal/renderer/api/ipc-renderer').default;
 

lib/sandboxed_renderer/init.ts

@@ -89,6 +89,9 @@ Object.defineProperty(preloadProcess, 'noDeprecation', {
   }
 });
 
+const contextId = v8Util.getHiddenValue<string>(global, 'contextId');
+Object.defineProperty(process, 'contextId', { get: () => contextId });
+
 process.on('loaded', () => (preloadProcess as events.EventEmitter).emit('loaded'));
 process.on('exit', () => (preloadProcess as events.EventEmitter).emit('exit'));
 (process as events.EventEmitter).on('document-start', () => (preloadProcess as events.EventEmitter).emit('document-start'));