Add LOCAL_ prefix to non-UMA histogram macros.

base/metrics/histogram.cc

Index: base/metrics/histogram.cc
diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index beb9b9e88989908cc4243062e71e718245321a02..6e30892179a7c83d60b7188d1393fba3c7c1b226 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -132,14 +132,6 @@ HistogramBase* Histogram::FactoryTimeGet(const string& name,
                     bucket_count, flags);
 }
 
-TimeTicks Histogram::DebugNow() {
-#ifndef NDEBUG
-  return TimeTicks::Now();
-#else
-  return TimeTicks();
-#endif
-}
-
 // Calculate what range of values are held in each bucket.
 // We have to be careful that we don't pick a ratio between starting points in
 // consecutive buckets that is sooo small, that the integer bounds are the same