Disable fetching of policy for login screen apps

chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h

Index: chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h
diff --git a/chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h b/chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h
index a7a734c21e73f110d4e57da53f2df08c0f8522b8..7a30322ceee7f429be3d66b31bbfab09997e0834 100644
--- a/chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h
+++ b/chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h
@@ -176,7 +176,11 @@ class DeviceCloudPolicyManagerChromeOS : public CloudPolicyManager {
       signin_profile_forwarding_schema_registry_;
 
   // Whether the component cloud policy service should be created.
-  bool is_component_policy_enabled_ = true;
+  // TODO(emaxx): Change the default to true once both the client and the
+  // DMServer are ready for handling policy fetches with the
+  // google/chromeos/signinextension type. See crbug.com/666720,
+  // crbug.com/644304 for reference.
+  bool is_component_policy_enabled_ = false;
 
   base::ObserverList<Observer, true> observers_;