Google Assistant request sync service (#10165)

* Initial commit for request_sync functionality

* Fixes for Tox results

* Fixed all tox issues and tested locally with GA

* Review comments - api_key, conditional read descriptions

* Add test for service

homeassistant/components/google_assistant/http.py

@@ -21,10 +21,16 @@ from homeassistant.core import HomeAssistant  # NOQA
 from homeassistant.helpers.entity import Entity  # NOQA
 
 from .const import (
-    CONF_ACCESS_TOKEN, CONF_EXPOSED_DOMAINS, ATTR_GOOGLE_ASSISTANT,
-    CONF_EXPOSE_BY_DEFAULT, DEFAULT_EXPOSED_DOMAINS, DEFAULT_EXPOSE_BY_DEFAULT,
-    GOOGLE_ASSISTANT_API_ENDPOINT)
-from .smart_home import query_device, entity_to_device, determine_service
+    GOOGLE_ASSISTANT_API_ENDPOINT,
+    CONF_ACCESS_TOKEN,
+    DEFAULT_EXPOSE_BY_DEFAULT,
+    DEFAULT_EXPOSED_DOMAINS,
+    CONF_EXPOSE_BY_DEFAULT,
+    CONF_EXPOSED_DOMAINS,
+    ATTR_GOOGLE_ASSISTANT,
+    CONF_AGENT_USER_ID
+    )
+from .smart_home import entity_to_device, query_device, determine_service
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -45,6 +51,7 @@ class GoogleAssistantView(HomeAssistantView):
                                          DEFAULT_EXPOSE_BY_DEFAULT)
         self.exposed_domains = cfg.get(CONF_EXPOSED_DOMAINS,
                                        DEFAULT_EXPOSED_DOMAINS)
+        self.agent_user_id = cfg.get(CONF_AGENT_USER_ID)
 
     def is_entity_exposed(self, entity) -> bool:
         """Determine if an entity should be exposed to Google Assistant."""
@@ -82,7 +89,9 @@ class GoogleAssistantView(HomeAssistantView):
             devices.append(device)
 
         return self.json(
-            make_actions_response(request_id, {'devices': devices}))
+            make_actions_response(request_id,
+                                  {'agentUserId': self.agent_user_id,
+                                   'devices': devices}))
 
     @asyncio.coroutine
     def handle_query(self,