OneGoogleBar on local NTP: wait for response before using cached data

It's not always safe to use cached data for the OneGoogleBar. For now,
always wait for the network request to come back before serving the OGB.
This is similar to the behavior of the remote NTP.
This also allows us to simplify the observer interface a bit.
Note that if the network request fails due to a transient error, the
cached data is still used.

Bug: 742937
Change-Id: Iadd2e72bfe06265d006629719c4792b2aefd15ec
Reviewed-on: https://chromium-review.googlesource.com/593909
Reviewed-by: Chris Pickel <[email protected]>
Commit-Queue: Marc Treib <[email protected]>
Cr-Commit-Position: refs/heads/master@{#490954}
diff --git a/chrome/browser/search/local_ntp_source.h b/chrome/browser/search/local_ntp_source.h
index 0187d5f..97ab154 100644
--- a/chrome/browser/search/local_ntp_source.h
+++ b/chrome/browser/search/local_ntp_source.h
@@ -59,8 +59,7 @@
   std::string GetContentSecurityPolicyChildSrc() const override;
 
   // Overridden from OneGoogleBarServiceObserver:
-  void OnOneGoogleBarDataChanged() override;
-  void OnOneGoogleBarFetchFailed() override;
+  void OnOneGoogleBarDataUpdated() override;
   void OnOneGoogleBarServiceShuttingDown() override;
 
   void ServeOneGoogleBar(const base::Optional<OneGoogleBarData>& data);