Return a NULL histogram pointer on construction error

chrome/browser/extensions/api/metrics_private/metrics_private_api.cc

Index: chrome/browser/extensions/api/metrics_private/metrics_private_api.cc
diff --git a/chrome/browser/extensions/api/metrics_private/metrics_private_api.cc b/chrome/browser/extensions/api/metrics_private/metrics_private_api.cc
index 89d1d9d40e5c39368124f745031273a9f17d352a..168d1a67b97fb01f6d53ea88cac0bc83a492fb97 100644
--- a/chrome/browser/extensions/api/metrics_private/metrics_private_api.cc
+++ b/chrome/browser/extensions/api/metrics_private/metrics_private_api.cc
@@ -139,7 +139,10 @@ bool MetricsHistogramHelperFunction::RecordValue(
         base::HistogramBase::kUmaTargetedHistogramFlag);
   }
 
-  counter->Add(sample);
+  // The histogram can be NULL if it is constructed with bad arguments.  Ignore
+  // that data for this API.  An error message will be logged.
+  if (counter)
+    counter->Add(sample);
   return true;
 }