Merge histograms from providers into StatisticsRecorder for display.

components/metrics/metrics_provider.h

Index: components/metrics/metrics_provider.h
diff --git a/components/metrics/metrics_provider.h b/components/metrics/metrics_provider.h
index 21cd17f995a214e5d6ae85a12d1cced49a7fc3c7..54c0a8949042360ae3ef7f5b6be52547a21efc9f 100644
--- a/components/metrics/metrics_provider.h
+++ b/components/metrics/metrics_provider.h
@@ -76,10 +76,6 @@ class MetricsProvider {
   virtual void ProvideGeneralMetrics(
       ChromeUserMetricsExtension* uma_proto);
 
-  // Called during regular collection to explicitly merge histogram deltas
-  // to the global StatisticsRecorder.
-  virtual void MergeHistogramDeltas();
-
   // Called during regular collection to explicitly load histogram snapshots
   // using a snapshot manager. PrepareDeltas() will have already been called
   // and FinishDeltas() will be called later; calls to only PrepareDelta(),