[WPT] Properly ignore DIR_METADATA and OWNERS in lint

`wpt lint --ignore-glob` uses fnmatch to match patterns, which means
1. Patterns must match the full filename (we need a wildcard at the
   beginning).
2. Path separators are not treated specially (i.e. we need to use
   platform-dependent path separators).

Furthermore, we need to ignore OWNERS files, too, which was forgotten in
an earlier change.

Add tests to prevent regressions.

Fixed: 1103374
Change-Id: I62e6ea5ebef900c60b10a325f01683fa5ed836c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2326110
Commit-Queue: Robert Ma <robertma@chromium.org>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Auto-Submit: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792792}

third_party/blink/web_tests/external/PRESUBMIT.py

@@ -17,9 +17,8 @@ def _LintWPT(input_api, output_api):
     information about the lint tool.
     """
     wpt_path = input_api.os_path.join(input_api.PresubmitLocalPath(), 'wpt')
-    linter_path = input_api.os_path.join(
-        input_api.PresubmitLocalPath(), '..', '..', '..', 'blink', 'tools',
-        'blinkpy', 'third_party', 'wpt', 'wpt', 'wpt')
+    linter_path = input_api.os_path.join(input_api.PresubmitLocalPath(), '..', '..', 'tools', 'blinkpy', 'third_party', 'wpt',
+                                         'wpt', 'wpt')
 
     paths_in_wpt = []
     for abs_path in input_api.AbsoluteLocalPaths():
@@ -38,7 +37,8 @@ def _LintWPT(input_api, output_api):
         'lint',
         '--repo-root=%s' % wpt_path,
         '--ignore-glob=*-expected.txt',
-        '--ignore-glob=DIR_METADATA',
+        '--ignore-glob=*DIR_METADATA',
+        '--ignore-glob=*OWNERS',
     ] + paths_in_wpt
 
     proc = input_api.subprocess.Popen(

third_party/blink/web_tests/external/PRESUBMIT_test.py

@@ -4,6 +4,7 @@
 # found in the LICENSE file.
 
 import os
+import shutil
 import subprocess
 import sys
 import unittest
@@ -76,9 +77,13 @@ class MockFile(object):
 class LintWPTTest(unittest.TestCase):
     def setUp(self):
         self._test_file = os.path.join(os.path.dirname(__file__), 'wpt', '_DO_NOT_SUBMIT_.html')
+        self._ignored_directory = os.path.join(os.path.dirname(__file__), 'wpt', 'css', '_DNS_')
 
     def tearDown(self):
-        os.remove(self._test_file)
+        if os.path.exists(self._test_file):
+            os.remove(self._test_file)
+        if os.path.exists(self._ignored_directory):
+            shutil.rmtree(self._ignored_directory)
 
     def testWPTLintSuccess(self):
         with open(self._test_file, 'w') as f:
@@ -99,6 +104,19 @@ class LintWPTTest(unittest.TestCase):
         errors = PRESUBMIT._LintWPT(mock_input, mock_output)
         self.assertEqual(len(errors), 1)
 
+    def testWPTLintIgnore(self):
+        os.mkdir(self._ignored_directory)
+        files = []
+        for f in ['DIR_METADATA', 'OWNERS', 'test-expected.txt']:
+            path = os.path.abspath(os.path.join(self._ignored_directory, f))
+            files.append(path)
+            open(path, 'w').close()
+        mock_input = MockInputApi()
+        mock_output = MockOutputApi()
+        mock_input.affected_paths = files
+        errors = PRESUBMIT._LintWPT(mock_input, mock_output)
+        self.assertEqual(len(errors), 0)
+
 
 class DontModifyIDLFilesTest(unittest.TestCase):
     def testModifiesIDL(self):