Remove assert on X from chromedriver.

BUG=chromium:413075
TEST=None.

Change-Id: Id131b8c28156f4653934f3e293feb32a6eb856d4
Reviewed-on: https://chromium-review.googlesource.com/276551
Tested-by: Ilja Friedel <ihf@chromium.org>
Reviewed-by: Haixia Shi <hshi@chromium.org>
diff --git a/client/common_lib/cros/chromedriver.py b/client/common_lib/cros/chromedriver.py
index 2a3808c..0ed832d 100644
--- a/client/common_lib/cros/chromedriver.py
+++ b/client/common_lib/cros/chromedriver.py
@@ -146,9 +146,9 @@
             port = utils.get_unused_port()
         chromedriver_args.append('--port=%d' % port)
 
+        # TODO(ihf): Remove references to X after M45.
         # Chromedriver will look for an X server running on the display
         # specified through the DISPLAY environment variable.
-        utils.assert_has_X_server()
         os.environ['DISPLAY'] = X_SERVER_DISPLAY
         os.environ['XAUTHORITY'] = X_AUTHORITY