Restrict sending GWS ID only to signed in users

chrome/browser/android/data_usage/external_data_use_observer.h

Index: chrome/browser/android/data_usage/external_data_use_observer.h
diff --git a/chrome/browser/android/data_usage/external_data_use_observer.h b/chrome/browser/android/data_usage/external_data_use_observer.h
index 97d8f95554d1d9b18fb01ef57fc4406a0841605e..c6ab83c9c4cc689d57d185d96d9a2b4371f80cb5 100644
--- a/chrome/browser/android/data_usage/external_data_use_observer.h
+++ b/chrome/browser/android/data_usage/external_data_use_observer.h
@@ -78,6 +78,8 @@ class ExternalDataUseObserver : public data_usage::DataUseAggregator::Observer {
     return external_data_use_reporter_;
   }
 
+  void SetRegisterGoogleVariationID(bool register_google_variation_id);
+
  private:
   friend class DataUseTabModelTest;
   friend class DataUseUITabModelTest;