Prerender: update historgram utility functions.

chrome/browser/prerender/prerender_histograms.cc

Index: chrome/browser/prerender/prerender_histograms.cc
diff --git a/chrome/browser/prerender/prerender_histograms.cc b/chrome/browser/prerender/prerender_histograms.cc
index d7ea7309607e65c57d8c91aa51bf9107d45037cc..2a7c5a3e634d0efcb90ad0724556df0b79d44704 100644
--- a/chrome/browser/prerender/prerender_histograms.cc
+++ b/chrome/browser/prerender/prerender_histograms.cc
@@ -36,31 +36,6 @@ int GetResourceType(bool is_main_resource, bool is_redirect, bool is_no_store) {
          (is_main_resource * MAIN_RESOURCE);
 }
 
-// Similar to UMA_HISTOGRAM_ENUMERATION but allows a dynamic histogram name.
-// Records a sample such as 0 <= sample < bucket_count, in a histogram with
-// |bucket_count| buckets of width 1 each.
-void RecordHistogramEnum(const std::string& histogram_name,
-                         base::HistogramBase::Sample sample,
-                         base::HistogramBase::Sample bucket_count) {
-  DCHECK_LT(sample, bucket_count);
-  base::HistogramBase* histogram_pointer = base::LinearHistogram::FactoryGet(
-      histogram_name, 1, bucket_count, bucket_count + 1,
-      base::HistogramBase::kUmaTargetedHistogramFlag);
-  histogram_pointer->Add(sample);
-}
-
-// Similar to UMA_HISTOGRAM_CUSTOM_TIMES but allows a dynamic histogram name.
-void RecordHistogramTime(const std::string& histogram_name,
-                         base::TimeDelta time_min,
-                         base::TimeDelta time_max,
-                         base::TimeDelta sample,
-                         base::HistogramBase::Sample bucket_count) {
-  base::HistogramBase* histogram_pointer = base::Histogram::FactoryTimeGet(
-      histogram_name, time_min, time_max, bucket_count,
-      base::HistogramBase::kUmaTargetedHistogramFlag);
-  histogram_pointer->AddTime(sample);
-}
-
 // Time window for which we will record windowed PLTs from the last observed
 // link rel=prefetch tag. This is not intended to be the same as the prerender
 // ttl, it's just intended to be a window during which a prerender has likely
@@ -440,8 +415,8 @@ void PrerenderHistograms::RecordPrefetchResponseReceived(
   int sample = GetResourceType(is_main_resource, is_redirect, is_no_store);
   std::string histogram_name =
       GetHistogramName(origin, IsOriginWash(), "NoStatePrefetchResponseTypes");
-  RecordHistogramEnum(histogram_name, sample,
-                      NO_STATE_PREFETCH_RESPONSE_TYPE_COUNT);
+  base::UmaHistogramExactLinear(histogram_name, sample,
+                                NO_STATE_PREFETCH_RESPONSE_TYPE_COUNT);
 }
 
 void PrerenderHistograms::RecordPrefetchRedirectCount(
@@ -455,7 +430,8 @@ void PrerenderHistograms::RecordPrefetchRedirectCount(
       "NoStatePrefetch%sResourceRedirects", is_main_resource ? "Main" : "Sub");
   std::string histogram_name =
       GetHistogramName(origin, IsOriginWash(), histogram_base_name);
-  RecordHistogramEnum(histogram_name, redirect_count, kMaxRedirectCount);
+  base::UmaHistogramExactLinear(histogram_name, redirect_count,
+                                kMaxRedirectCount);
 }
 
 void PrerenderHistograms::RecordPrefetchFirstContentfulPaintTime(
@@ -468,9 +444,10 @@ void PrerenderHistograms::RecordPrefetchFirstContentfulPaintTime(
 
   if (!prefetch_age.is_zero()) {
     DCHECK_NE(origin, ORIGIN_NONE);
-    RecordHistogramTime(GetHistogramName(origin, IsOriginWash(), "PrefetchAge"),
-                        base::TimeDelta::FromMilliseconds(10),
-                        base::TimeDelta::FromMinutes(30), prefetch_age, 50);
+    base::UmaHistogramCustomTimes(
+        GetHistogramName(origin, IsOriginWash(), "PrefetchAge"), prefetch_age,
+        base::TimeDelta::FromMilliseconds(10), base::TimeDelta::FromMinutes(30),
+        50);
   }
 
   std::string histogram_base_name;
@@ -488,8 +465,9 @@ void PrerenderHistograms::RecordPrefetchFirstContentfulPaintTime(
   std::string histogram_name =
       GetHistogramName(origin, IsOriginWash(), histogram_base_name);
 
-  RecordHistogramTime(histogram_name, base::TimeDelta::FromMilliseconds(10),
-                      base::TimeDelta::FromMinutes(2), time, 50);
+  base::UmaHistogramCustomTimes(histogram_name, time,
+                                base::TimeDelta::FromMilliseconds(10),
+                                base::TimeDelta::FromMinutes(2), 50);
 }
 
 bool PrerenderHistograms::IsOriginWash() const {