Add WPT tooling PRESUBMIT for loading the WPT manifest

Bug: 1095643
Change-Id: Ibbe7862d6ded259612c795c9933d3b2a7bd7aef5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2264861
Commit-Queue: Robert Ma <robertma@chromium.org>
Reviewed-by: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782715}

third_party/blink/tools/blinkpy/third_party/wpt/PRESUBMIT.py

@@ -4,11 +4,14 @@
 
 """Check the basic functionalities of WPT tools.
 
-After rolling a new version of WPT tools, we should do some sanity checks. For
-now, we only test `wpt lint` via web_tests/external/PRESUBMIT_test.py.
+This PRESUBMIT guards against rolling a broken version of WPT tooling. It does
+some smoke checks of WPT functionality.
 """
 
+
 def _TestWPTLint(input_api, output_api):
+  # We test 'wpt lint' by deferring to the web_tests/external presubmit test,
+  # which runs 'wpt lint' against web_tests/external/wpt.
   abspath_to_test = input_api.os_path.join(
     input_api.change.RepositoryRoot(),
     'third_party', 'blink', 'web_tests', 'external', 'PRESUBMIT_test.py'
@@ -24,9 +27,41 @@ def _TestWPTLint(input_api, output_api):
   return input_api.RunTests([command])
 
 
+def _TestWPTManifest(input_api, output_api):
+  # We test 'wpt manifest' by making a copy of the base manifest and updating
+  # it. A copy is used so that this PRESUBMIT doesn't change files in the tree.
+  blink_path = input_api.os_path.join(
+      input_api.change.RepositoryRoot(), 'third_party', 'blink')
+
+  base_manifest = input_api.os_path.join(
+      blink_path, 'web_tests', 'external', 'WPT_BASE_MANIFEST_8.json')
+  with input_api.CreateTemporaryFile() as f:
+    f.write(input_api.ReadFile(base_manifest))
+    f.close()
+
+    wpt_exec_path = input_api.os_path.join(
+        blink_path, 'tools', 'blinkpy', 'third_party', 'wpt', 'wpt', 'wpt')
+    external_wpt = input_api.os_path.join(
+        blink_path, 'web_tests', 'external', 'wpt')
+    try:
+      input_api.subprocess.check_output(
+          ['python', wpt_exec_path, 'manifest', '--no-download',
+           '--path', f.name, '--tests-root', external_wpt])
+    except input_api.subprocess.CalledProcessError as exc:
+      return [output_api.PresubmitError('wpt manifest failed:', long_text=exc.output)]
+
+  return []
+
+
 def CheckChangeOnUpload(input_api, output_api):
-  return _TestWPTLint(input_api, output_api)
+  results = []
+  results += _TestWPTLint(input_api, output_api)
+  results += _TestWPTManifest(input_api, output_api)
+  return results
 
 
 def CheckChangeOnCommit(input_api, output_api):
-  return _TestWPTLint(input_api, output_api)
+  results = []
+  results += _TestWPTLint(input_api, output_api)
+  results += _TestWPTManifest(input_api, output_api)
+  return results