Clarify AndroidStatusFetcher documentation

chrome/browser/chromeos/policy/device_status_collector.h

Index: chrome/browser/chromeos/policy/device_status_collector.h
diff --git a/chrome/browser/chromeos/policy/device_status_collector.h b/chrome/browser/chromeos/policy/device_status_collector.h
index b4988191055e9c6b47a28b6118bc64736901fb29..8e44f429ad0d9483300d56385c1bceb4fd068c7d 100644
--- a/chrome/browser/chromeos/policy/device_status_collector.h
+++ b/chrome/browser/chromeos/policy/device_status_collector.h
@@ -68,7 +68,10 @@ class DeviceStatusCollector {
   using AndroidStatusReceiver =
       base::Callback<void(const std::string&, const std::string&)>;
   // Calls the enterprise reporting mojo interface, passing over the
-  // AndroidStatusReceiver.
+  // AndroidStatusReceiver. Returns false if the mojo interface isn't available,
+  // in which case no asynchronous query is emitted and the android status query
+  // fails synchronously. The |AndroidStatusReceiver| is not called in this
+  // case.
   using AndroidStatusFetcher =
       base::Callback<bool(const AndroidStatusReceiver&)>;