diag - add a cli arg to open devtools when window opens

src/vs/code/electron-main/window.ts

@@ -215,6 +215,11 @@ export class CodeWindow extends Disposable implements ICodeWindow {
 			this._win = new BrowserWindow(options);
 			this._id = this._win.id;
 
+			// Open devtools if instructed from command line args
+			if (this.environmentService.args['open-devtools'] === true) {
+				this._win.webContents.openDevTools();
+			}
+
 			if (isMacintosh && useCustomTitleStyle) {
 				this._win.setSheetOffset(22); // offset dialogs by the height of the custom title bar if we have any
 			}

src/vs/platform/environment/node/argv.ts

@@ -33,6 +33,7 @@ export interface ParsedArgs {
 	trace?: boolean;
 	'trace-category-filter'?: string;
 	'trace-options'?: string;
+	'open-devtools'?: boolean;
 	log?: string;
 	logExtensionHostCommunication?: boolean;
 	'extensions-dir'?: string;
@@ -193,6 +194,7 @@ export const OPTIONS: OptionDescriptions<Required<ParsedArgs>> = {
 	'trace-category-filter': { type: 'string' },
 	'trace-options': { type: 'string' },
 	'force-user-env': { type: 'boolean' },
+	'open-devtools': { type: 'boolean' },
 
 	// chromium flags
 	'no-proxy-server': { type: 'boolean' },