Don't check for redundant virtual expectations during presubmit

Because of crbug.com/1080691, WPT import constantly adds redundant
virtual expectations, and the warnings (though not errors) are
annoying to most developers.

Actually the virtual fallback feature was to relieve burden of
sheriffs and developers for adding duplicated virtual and base
expectations. Preventing redundant expectations is not the main goal.
Existing redundant expectations are not very harmful.

Bug: 1080691
Change-Id: Id0a4ac931d417a223d337cd260aba47ddd74395f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2227454
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Auto-Submit: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774730}

third_party/blink/tools/blinkpy/web_tests/lint_test_expectations.py

@@ -48,7 +48,10 @@ def PresubmitCheckTestExpectations(input_api, output_api):
         os_path.dirname(os_path.abspath(__file__)), '..', '..',
         'lint_test_expectations.py')
     _, errs = input_api.subprocess.Popen(
-        [input_api.python_executable, lint_path],
+        [
+            input_api.python_executable, lint_path,
+            '--no-check-redundant-virtual-expectations'
+        ],
         stdout=input_api.subprocess.PIPE,
         stderr=input_api.subprocess.PIPE).communicate()
     if not errs:
@@ -125,7 +128,7 @@ def lint(host, options):
                 ports_to_lint[0], expectations_dict={path: content})
             # Check each expectation for issues
             f, w = _check_expectations(host, ports_to_lint[0], path,
-                                       test_expectations)
+                                       test_expectations, options)
             failures += f
             warnings += w
         except ParseError as error:
@@ -246,7 +249,7 @@ def _check_redundant_virtual_expectations(host, port, path, expectations):
     return failures
 
 
-def _check_expectations(host, port, path, test_expectations):
+def _check_expectations(host, port, path, test_expectations, options):
     # Check for original expectation lines (from get_updated_lines) instead of
     # expectations filtered for the current port (test_expectations).
     expectations = test_expectations.get_updated_lines(path)
@@ -254,8 +257,11 @@ def _check_expectations(host, port, path, test_expectations):
     failures.extend(_check_directory_glob(host, port, path, expectations))
     # TODO(crbug.com/1080691): Change this to failures once
     # wpt_expectations_updater is fixed.
-    warnings = _check_redundant_virtual_expectations(host, port, path,
-                                                     expectations)
+    warnings = []
+    if not getattr(options, 'no_check_redundant_virtual_expectations', False):
+        warnings.extend(
+            _check_redundant_virtual_expectations(host, port, path,
+                                                  expectations))
     return failures, warnings
 
 
@@ -387,6 +393,10 @@ def main(argv, stderr, host=None):
         action='append',
         default=[],
         help='paths to additional expectation files to lint.')
+    parser.add_option('--no-check-redundant-virtual-expectations',
+                      action='store_true',
+                      default=False,
+                      help='skip checking redundant virtual expectations.')
 
     options, _ = parser.parse_args(argv)