Add option to turn on accessibility for chrome family

Author: spectranaut

tools/wpt/run.py

@@ -519,7 +519,8 @@ def setup_kwargs(self, kwargs):
             # We are on Taskcluster, where our Docker container does not have
             # enough capabilities to run Chrome with sandboxing. (gh-20133)
             kwargs["binary_args"].append("--no-sandbox")
-
+        if kwargs["force_renderer_accessibility"]:
+            kwargs["binary_args"].append("--force-renderer-accessibility")
 
 class ContentShell(BrowserSetup):
     name = "content_shell"

tools/wptrunner/wptrunner/wptcommandline.py

@@ -377,6 +377,8 @@ def create_parser(product_choices=None):
     chrome_group.add_argument("--no-enable-experimental", action="store_false", dest="enable_experimental",
                               help="Do not enable --enable-experimental-web-platform-features flag "
                               "on experimental channels")
+    chrome_group.add_argument( "--force-renderer-accessibility", action="store_true",
+                              dest="force_renderer_accessibility",help="Turn on accessibility.")
     chrome_group.add_argument(
         "--enable-sanitizer",
         action="store_true",