More WPT waterfall timeout debugging:

- enable verbose logging.
- try skipping webdriver tests, which seem related to the timeouts.

Also proposing to add per-file owners for testing/scripts/run_wpt_tests.py
to enable quicker poking at these flags in the near term.

Bug: 1023835
Change-Id: I1d7b7b7f08adea6a8f33ff722458faf3bacacbde
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1906897
Commit-Queue: Luke Z <lpz@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714538}

testing/scripts/OWNERS

@@ -9,5 +9,8 @@ martiniss@chromium.org
 per-file check_static_initializers.py=thakis@chromium.org
 per-file check_static_initializers.py=thomasanderson@chromium.org
 
+per-file run-wpt_tests.py=lpz@chromium.org
+per-file run_wpt_tests.py=robertma@chromium.org
+
 # TEAM: infra-dev@chromium.org
 # COMPONENT: Infra>Client>Chrome

testing/scripts/run_wpt_tests.py

@@ -72,8 +72,10 @@ class WPTTestAdapter(common.BaseIsolatedScriptArgsAdapter):
             #"--no-manifest-update",
             "--manifest=../../third_party/blink/web_tests/external/"
                 "WPT_BASE_MANIFEST_6.json",
-            # Enable mach logging to aid debugging
-            "--log-mach=-"
+            # (crbug.com/1023835) The flags below are temporary to aid debugging
+            "--log-mach=-",
+            "--log-mach-verbose",
+            "--exclude=webdriver"
         ])
         return rest_args