Fix wptserve in run_webdriver_tests

Following https://crrev.com/c/1641436, wptserve needs to have an output
directory to redirect its logs to (same as Apache). However,
run_webdriver_tests.py didn't set the output directory of the port
object ("results-directory") previously, so it would default to
out/Release/layout-test-results, which does not exist on the bot.

This change adds a new --output-dir argument to run_webdriver_tests.py
and sets it to ISOLATED_OUTDIR on Swarming and a temporary directory
locally (when the argument isn't present).

In addition, wptserve.py is reverted back to conditionally add
--ws_doc_root as run_webdriver_tests does not have WebSocket handlers.

Drive-by change: remove the redundant --isolated-script-test-output
flag from gn_isolate_map.pyl as the isolated script runner already
adds that flag automatically.

Bug: 968904, 972005
Change-Id: Id066981b7eee6585de56dfa62e750b367b965843
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1649382
Reviewed-by: John Chen <johnchen@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Auto-Submit: Robert Ma <robertma@chromium.org>
Commit-Queue: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#668016}

chrome/test/chromedriver/test/run_webdriver_tests.py

@@ -9,6 +9,7 @@
 import argparse
 import sys
 import json
+import tempfile
 import time
 import logging
 
@@ -181,6 +182,9 @@ def run_test(path, path_finder, port, skipped_tests=[]):
       help='Output verbose server logs to this file')
   parser.add_argument(
       '--chrome', help='Path to chrome binary')
+  parser.add_argument(
+      '--output-dir',
+      help='Output directory for misc logs (e.g. wptserve)')
   parser.add_argument(
       '--isolated-script-test-output',
       help='JSON output file used by swarming')
@@ -211,6 +215,12 @@ def run_test(path, path_finder, port, skipped_tests=[]):
 
   host = Host()
   port = host.port_factory.get()
+  if options.output_dir:
+    port.set_option_default('results_directory', options.output_dir)
+  else:
+    output_dir = tempfile.mkdtemp('webdriver_tests')
+    _log.info('Using a temporary output dir %s', output_dir)
+    port.set_option_default('results_directory', output_dir)
   path_finder = PathFinder(host.filesystem)
 
   # Starts WPT Serve to serve the WPT WebDriver test content.

testing/buildbot/gn_isolate_map.pyl

@@ -640,7 +640,7 @@
       "../../chrome/test/chromedriver/test/run_webdriver_tests.py",
       "-v",
       "--chromedriver=chromedriver",
-      "--isolated-script-test-output=${ISOLATED_OUTDIR}/results.json",
+      "--output-dir=${ISOLATED_OUTDIR}",
       "--test-path=../../third_party/blink/web_tests/external/wpt/webdriver/tests/",
     ],
   },

third_party/blink/tools/blinkpy/web_tests/servers/wptserve.py

@@ -45,8 +45,12 @@ def __init__(self, port_obj, output_dir):
         start_cmd = [self._port_obj.host.executable,
                      '-u', wpt_script, 'serve',
                      '--config', self._config_file,
-                     '--doc_root', path_to_wpt_tests,
-                     '--ws_doc_root', path_to_ws_handlers]
+                     '--doc_root', path_to_wpt_tests]
+
+        # Some users (e.g. run_webdriver_tests.py) do not need WebSocket
+        # handlers, so we only add the flag if the directory exists.
+        if self._port_obj.host.filesystem.exists(path_to_ws_handlers):
+            start_cmd += ['--ws_doc_root', path_to_ws_handlers]
 
         # TODO(burnik): We should stop setting the CWD once WPT can be run without it.
         self._cwd = path_to_wpt_root

third_party/blink/tools/blinkpy/web_tests/servers/wptserve_unittest.py

@@ -25,7 +25,24 @@ def setUp(self):
 
     # pylint: disable=protected-access
 
-    def test_init_start_cmd(self):
+    def test_init_start_cmd_without_ws_handlers(self):
+        server = WPTServe(self.port, '/foo')
+        self.assertEqual(
+            server._start_cmd,  # pylint: disable=protected-access
+            [
+                'python',
+                '-u',
+                '/mock-checkout/third_party/blink/tools/blinkpy/third_party/wpt/wpt/wpt',
+                'serve',
+                '--config',
+                server._config_file,
+                '--doc_root',
+                '/test.checkout/wtests/external/wpt',
+            ])
+
+    def test_init_start_cmd_with_ws_handlers(self):
+        self.host.filesystem.maybe_make_directory(
+            '/test.checkout/wtests/external/wpt/websockets/handlers')
         server = WPTServe(self.port, '/foo')
         self.assertEqual(
             server._start_cmd,  # pylint: disable=protected-access
@@ -39,7 +56,7 @@ def test_init_start_cmd(self):
                 '--doc_root',
                 '/test.checkout/wtests/external/wpt',
                 '--ws_doc_root',
-                '/test.checkout/wtests/external/wpt/websockets/handlers'
+                '/test.checkout/wtests/external/wpt/websockets/handlers',
             ])
 
     def test_init_gen_config(self):