Fix iOS wptrunner to wait for simulator start. (#46292)

* Fix iOS wptrunner to wait for simulator start.

Author: sj0602

tools/wptrunner/wptrunner/browsers/chrome_ios.py

@@ -1,7 +1,9 @@
 # mypy: allow-untyped-defs
 
+import traceback
 from .base import WebDriverBrowser, require_arg
 from .base import get_timeout_multiplier   # noqa: F401
+from ..environment import wait_for_service
 from ..executors import executor_kwargs as base_executor_kwargs
 from ..executors.base import WdspecExecutor  # noqa: F401
 from ..executors.executorchrome import ChromeDriverPrintRefTestExecutor  # noqa: F401
@@ -60,3 +62,19 @@ class ChromeiOSBrowser(WebDriverBrowser):
     def make_command(self):
         return ([self.webdriver_binary, f"--port={self.port}"] +
                 self.webdriver_args)
+
+    def start(self, group_metadata, **kwargs):
+        super().start(group_metadata, **kwargs)
+        try:
+            wait_for_service(
+                self.logger,
+                self.host,
+                self.port,
+                timeout=self.init_timeout,
+                server_process=self._proc,
+            )
+        except Exception:
+            self.logger.error(
+                "WebDriver was not accessible "
+                f"within the timeout:\n{traceback.format_exc()}")
+            raise