Remove unused memory usage collection in MetricsService

chrome/browser/metrics/metrics_service.h

Index: chrome/browser/metrics/metrics_service.h
diff --git a/chrome/browser/metrics/metrics_service.h b/chrome/browser/metrics/metrics_service.h
index 48e2cd146fa41e6d66478472b55fc6e920cd2b9a..59322886521eeb26cf005450c86ff1f115cdd635 100644
--- a/chrome/browser/metrics/metrics_service.h
+++ b/chrome/browser/metrics/metrics_service.h
@@ -230,10 +230,8 @@ class MetricsService : public NotificationObserver,
   // Internal function to collect process memory information.
   void LogTransmissionTimerDone();
 
-  // Do not call OnMemoryDetailCollectionDone() or
-  // OnHistogramSynchronizationDone() directly.
+  // Do not call OnHistogramSynchronizationDone() directly.
   // Use StartLogTransmissionTimer() to schedule a call.
-  void OnMemoryDetailCollectionDone();
   void OnHistogramSynchronizationDone();
 
   // Takes whatever log should be uploaded next (according to the state_)