webrtc: prepare for running under remote_run

scripts/slave/recipe_modules/webrtc/api.py

Index: scripts/slave/recipe_modules/webrtc/api.py
diff --git a/scripts/slave/recipe_modules/webrtc/api.py b/scripts/slave/recipe_modules/webrtc/api.py
index c082cfa89561b03b168d79ff12ad5a91d246a366..0d0cecf99aa8319639f7f25dc1e29d20e81edb81 100644
--- a/scripts/slave/recipe_modules/webrtc/api.py
+++ b/scripts/slave/recipe_modules/webrtc/api.py
@@ -144,6 +144,10 @@ class WebRTCApi(recipe_api.RecipeApi):
               self.m.platform.name).split('-', 1)[0])
 
   def checkout(self, **kwargs):
+    checkout_dir = self.m.chromium_tests.get_checkout_dir({})
+    if checkout_dir:
+      kwargs.setdefault('cwd', checkout_dir)
+
     update_step = self.m.bot_update.ensure_checkout(**kwargs)
     assert update_step.json.output['did_run']