Regenerate MANIFEST.json when WPT tests are run

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
index 3c4728110f8fdb520e419a308666237faa51b436..14b24ea60b829f5d28aa929511e0f98eb96f7406 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
@@ -756,8 +756,18 @@ class Port(object):
 
     @memoized
     def _wpt_manifest(self):
-        path = self._filesystem.join(self.layout_tests_dir(), 'external', 'wpt', 'MANIFEST.json')
-        return json.loads(self._filesystem.read_text_file(path))
+        manifest_path = self._filesystem.join(self.layout_tests_dir(), 'external', 'wpt', 'MANIFEST.json')
+        self._generate_manifest()
+        return json.loads(self._filesystem.read_text_file(manifest_path))
+
+    def _generate_manifest(self):
+        wpt_path = self._webkit_finder.path_from_webkit_base('LayoutTests', 'external', 'wpt')
+        manifest_tool_path = self._webkit_finder.path_from_webkit_base(
+            'Tools', 'Scripts', 'webkitpy', 'thirdparty', 'wpt', 'wpt', 'manifest')
+        _log.info(('Generating MANIFEST.json, this might result in changes ',
+                   'to MANIFEST.json in your working directory. Please commit them along ',
+                   'with your changes. See https://crbug.com/666957.'))

[qyearsley, 2017/01/27 23:24:49]

Can you call log methods with a tuple like this? I think that this might result
in just logging a stringified tuple. In most places we print long messages with
either:

        _log.info('Generating MANIFEST.json, this might result in changes to
MANIFEST.json\n'
                  'in your working directory. Please commit them along with your
changes.\n'
                  'See https://crbug.com/666957.')

or:
        _log.info('Generating MANIFEST.json, this might result in changes to
MANIFEST.json')
        _log.info('in your working directory. Please commit them along with your
changes.')
        _log.info('See https://crbug.com/666957.')

Anyway, I think this message is good for now but seems like a temporary thing.
I wonder what the ideal behavior should be? I'm imagining maybe the ideal
behavior might
be still be staging the change for you if necessary and only printing a message
when
a change was made?

+        self._executive.run_command([manifest_tool_path, '--work', '--tests-root', wpt_path])
 
     def _manifest_items_for_path(self, path_in_wpt):
         """Returns a manifest item for the given WPT path, or None if not found.