fix: trace-startup crashing child process on macOS (#44257)

spec/chromium-spec.ts

@@ -15,7 +15,7 @@ import * as path from 'node:path';
 import { setTimeout } from 'node:timers/promises';
 import * as url from 'node:url';
 
-import { ifit, ifdescribe, defer, itremote, listen } from './lib/spec-helpers';
+import { ifit, ifdescribe, defer, itremote, listen, startRemoteControlApp } from './lib/spec-helpers';
 import { closeAllWindows } from './lib/window-helpers';
 import { PipeTransport } from './pipe-transport';
 
@@ -556,6 +556,36 @@ describe('command line switches', () => {
       });
     });
   });
+
+  describe('--trace-startup switch', () => {
+    const outputFilePath = path.join(app.getPath('temp'), 'trace.json');
+    afterEach(() => {
+      if (fs.existsSync(outputFilePath)) {
+        fs.unlinkSync(outputFilePath);
+      }
+    });
+
+    it('creates startup trace', async () => {
+      const rc = await startRemoteControlApp(['--trace-startup=*', `--trace-startup-file=${outputFilePath}`, '--trace-startup-duration=1', '--enable-logging']);
+      const stderrComplete = new Promise<string>(resolve => {
+        let stderr = '';
+        rc.process.stderr!.on('data', (chunk) => {
+          stderr += chunk.toString('utf8');
+        });
+        rc.process.on('close', () => { resolve(stderr); });
+      });
+      rc.remotely(() => {
+        global.setTimeout(() => {
+          require('electron').app.quit();
+        }, 5000);
+      });
+      const stderr = await stderrComplete;
+      expect(stderr).to.match(/Completed startup tracing to/);
+      expect(fs.existsSync(outputFilePath)).to.be.true('output exists');
+      expect(fs.statSync(outputFilePath).size).to.be.above(0,
+        `the trace output file is empty, check "${outputFilePath}"`);
+    });
+  });
 });
 
 describe('chromium features', () => {