fix(launcher): make dumpio and pipe options work together (#4727)

Don't ignore stdout and stderr when using pipe for remote debugging and dumpio is true. In that case puppeteer process connects to the stdout/stderr streams of the child process and it will not hang.

lib/Launcher.js

@@ -123,7 +123,13 @@ class Launcher {
 
     const usePipe = chromeArguments.includes('--remote-debugging-pipe');
     /** @type {!Array<"ignore"|"pipe">} */
-    const stdio = usePipe ? ['ignore', 'ignore', 'ignore', 'pipe', 'pipe'] : ['pipe', 'pipe', 'pipe'];
+    let stdio = ['pipe', 'pipe', 'pipe'];
+    if (usePipe) {
+      if (dumpio)
+        stdio = ['ignore', 'pipe', 'pipe', 'pipe', 'pipe'];
+      else
+        stdio = ['ignore', 'ignore', 'ignore', 'pipe', 'pipe'];
+    }
     const chromeProcess = childProcess.spawn(
         chromeExecutable,
         chromeArguments,

test/fixtures.spec.js

@@ -22,6 +22,16 @@ module.exports.addTests = function({testRunner, expect, defaultBrowserOptions, p
   const {beforeAll, beforeEach, afterAll, afterEach} = testRunner;
 
   describe('Fixtures', function() {
+    it_fails_ffox('dumpio option should work with pipe option ', async({server}) => {
+      let dumpioData = '';
+      const {spawn} = require('child_process');
+      const options = Object.assign({}, defaultBrowserOptions, {pipe: true, dumpio: true});
+      const res = spawn('node',
+          [path.join(__dirname, 'fixtures', 'dumpio.js'), puppeteerPath, JSON.stringify(options)]);
+      res.stderr.on('data', data => dumpioData += data.toString('utf8'));
+      await new Promise(resolve => res.on('close', resolve));
+      expect(dumpioData).toContain('message from dumpio');
+    });
     it('should dump browser process stderr', async({server}) => {
       let dumpioData = '';
       const {spawn} = require('child_process');

test/fixtures/dumpio.js

@@ -2,6 +2,7 @@
   const [, , puppeteerRoot, options] = process.argv;
   const browser = await require(puppeteerRoot).launch(JSON.parse(options));
   const page = await browser.newPage();
+  await page.evaluate(() => console.error('message from dumpio'));
   await page.close();
   await browser.close();
 })();