[wptrunner] Replace content_shell with headless_shell (#46658)

Chromium CI plans to replace `content_shell` [0] with `headless_shell`
[1] for running most WPTs. Replace the product accordingly, which is
mostly a `chrome` clone.

[0]: https://chromium.googlesource.com/chromium/src/+/HEAD/docs/testing/web_tests_in_content_shell.md
[1]: https://chromium.googlesource.com/chromium/src/+/HEAD/headless/README.md

Author: jonathan-j-lee

tools/wpt/browser.py

@@ -9,6 +9,7 @@
 from abc import ABCMeta, abstractmethod
 from datetime import datetime, timedelta, timezone
 from shutil import which
+from typing import Optional
 from urllib.parse import urlsplit
 
 import html5lib
@@ -583,7 +584,7 @@ class ChromeChromiumBase(Browser):
     see https://web-platform-tests.org/running-tests/chrome-chromium-installation-detection.html
     """
 
-    requirements = "requirements_chromium.txt"
+    requirements: Optional[str] = "requirements_chromium.txt"
     platform = {
         "Linux": "Linux",
         "Windows": "Win",
@@ -1392,14 +1393,17 @@ def webdriver_version(self, webdriver_binary):
         return m.group(1)
 
 
-class ContentShell(Browser):
-    """Interface for the Chromium content shell.
+class HeadlessShell(ChromeChromiumBase):
+    """Interface for the Chromium headless shell [0].
+
+    [0]: https://chromium.googlesource.com/chromium/src/+/HEAD/headless/README.md
     """
 
-    product = "content_shell"
+    product = "headless_shell"
     requirements = None
 
     def download(self, dest=None, channel=None, rename=None):
+        # TODO(crbug.com/344669542): Download binaries via CfT.
         raise NotImplementedError
 
     def install(self, dest=None, channel=None):
@@ -1409,17 +1413,16 @@ def install_webdriver(self, dest=None, channel=None, browser_binary=None):
         raise NotImplementedError
 
     def find_binary(self, venv_path=None, channel=None):
-        if uname[0] == "Darwin":
-            return which("Content Shell.app/Contents/MacOS/Content Shell")
-        return which("content_shell")  # .exe is added automatically for Windows
-
-    def find_webdriver(self, venv_path=None, channel=None):
-        return None
+        # `which()` adds `.exe` extension automatically for Windows.
+        # Chromium builds an executable named `headless_shell`, whereas CfT
+        # ships under the name `chrome-headless-shell`.
+        return which("headless_shell") or which("chrome-headless-shell")
 
     def version(self, binary=None, webdriver_binary=None):
-        # content_shell does not return version information.
+        # TODO(crbug.com/327767951): Support `headless_shell --version`.
         return "N/A"
 
+
 class ChromeAndroidBase(Browser):
     """A base class for ChromeAndroid and AndroidWebView.
 

tools/wpt/run.py

@@ -112,7 +112,7 @@ def set_if_none(name, value):
 
 def check_environ(product):
     if product not in ("android_webview", "chrome", "chrome_android", "chrome_ios",
-                       "content_shell", "edge", "firefox", "firefox_android",
+                       "edge", "firefox", "firefox_android", "headless_shell",
                        "ladybird", "servo", "wktr"):
         config_builder = serve.build_config(os.path.join(wpt_root, "config.json"))
         # Override the ports to avoid looking for free ports
@@ -521,9 +521,9 @@ def setup_kwargs(self, kwargs):
             kwargs["binary_args"].append("--no-sandbox")
 
 
-class ContentShell(BrowserSetup):
-    name = "content_shell"
-    browser_cls = browser.ContentShell
+class HeadlessShell(BrowserSetup):
+    name = "headless_shell"
+    browser_cls = browser.HeadlessShell
     experimental_channels = ("dev", "canary", "nightly")
 
     def setup_kwargs(self, kwargs):
@@ -533,7 +533,7 @@ def setup_kwargs(self, kwargs):
             if binary:
                 kwargs["binary"] = binary
             else:
-                raise WptrunError(f"Unable to locate {self.name.capitalize()} binary")
+                raise WptrunError(f"Unable to locate {self.name!r} binary")
 
         if kwargs["mojojs_path"]:
             kwargs["enable_mojojs"] = True
@@ -544,7 +544,13 @@ def setup_kwargs(self, kwargs):
                            "Provide '--mojojs-path' explicitly instead.")
             logger.warning("MojoJS is disabled for this run.")
 
-        kwargs["enable_webtransport_h3"] = True
+        # Never pause after test, since headless shell is not interactive.
+        kwargs["pause_after_test"] = False
+        # Don't add a `--headless` switch.
+        kwargs["headless"] = False
+
+        if kwargs["enable_webtransport_h3"] is None:
+            kwargs["enable_webtransport_h3"] = True
 
 
 class Chromium(Chrome):
@@ -867,8 +873,8 @@ def setup_kwargs(self, kwargs):
     "chrome_android": ChromeAndroid,
     "chrome_ios": ChromeiOS,
     "chromium": Chromium,
-    "content_shell": ContentShell,
     "edge": Edge,
+    "headless_shell": HeadlessShell,
     "safari": Safari,
     "servo": Servo,
     "servodriver": ServoWebDriver,

tools/wptrunner/wptrunner/browsers/__init__.py

@@ -27,10 +27,10 @@
                 "chrome_android",
                 "chrome_ios",
                 "chromium",
-                "content_shell",
                 "edge",
                 "firefox",
                 "firefox_android",
+                "headless_shell",
                 "safari",
                 "sauce",
                 "servo",

tools/wptrunner/wptrunner/browsers/content_shell.py

@@ -0,0 +1,62 @@
+# mypy: allow-untyped-defs
+
+from .base import cmd_arg, require_arg
+from .base import get_timeout_multiplier   # noqa: F401
+from .chrome import ChromeBrowser, debug_args, executor_kwargs  # noqa: F401
+from ..executors.base import WdspecExecutor  # noqa: F401
+from ..executors.executorchrome import (  # noqa: F401
+    ChromeDriverCrashTestExecutor,
+    ChromeDriverPrintRefTestExecutor,
+    ChromeDriverRefTestExecutor,
+    ChromeDriverTestharnessExecutor,
+)
+
+
+__wptrunner__ = {"product": "headless_shell",
+                 "check_args": "check_args",
+                 "browser": "HeadlessShellBrowser",
+                 "executor": {
+                     "crashtest": "ChromeDriverCrashTestExecutor",
+                     "print-reftest": "ChromeDriverPrintRefTestExecutor",
+                     "reftest": "ChromeDriverRefTestExecutor",
+                     "testharness": "ChromeDriverTestharnessExecutor",
+                     "wdspec": "WdspecExecutor",
+                 },
+                 "browser_kwargs": "browser_kwargs",
+                 "executor_kwargs": "executor_kwargs",
+                 "env_extras": "env_extras",
+                 "env_options": "env_options",
+                 "update_properties": "update_properties",
+                 "timeout_multiplier": "get_timeout_multiplier",}
+
+
+def check_args(**kwargs):
+    require_arg(kwargs, "webdriver_binary")
+
+
+def browser_kwargs(logger, test_type, run_info_data, config, **kwargs):
+    return {"binary": kwargs["binary"],
+            "webdriver_binary": kwargs["webdriver_binary"],
+            "webdriver_args": kwargs.get("webdriver_args"),
+            "debug_info": kwargs["debug_info"]}
+
+
+def env_extras(**kwargs):
+    return []
+
+
+def env_options():
+    return {"server_host": "127.0.0.1",
+            "supports_debugger": True}
+
+
+def update_properties():
+    return (["debug", "os", "processor"], {"os": ["version"], "processor": ["bits"]})
+
+
+class HeadlessShellBrowser(ChromeBrowser):
+    def make_command(self):
+        return [self.webdriver_binary,
+                cmd_arg("port", str(self.port)),
+                cmd_arg("url-base", self.base_path),
+                cmd_arg("enable-chrome-logs")] + self.webdriver_args