[py] Remove exceptions for browser_name and vendor_prefix

Author: cgoldberg

py/selenium/webdriver/chromium/webdriver.py

@@ -56,11 +56,6 @@ def __init__(
         self.service.path = self.service.env_path() or finder.get_driver_path()
         self.service.start()
 
-        if browser_name is None:
-            raise ValueError("browser_name must be specified")
-        if vendor_prefix is None:
-            raise ValueError("vendor_prefix must be specified")
-
         executor = ChromiumRemoteConnection(
             remote_server_addr=self.service.service_url,
             browser_name=browser_name,