Update from https://crrev.com/333737

base/metrics/statistics_recorder.cc

Index: base/metrics/statistics_recorder.cc
diff --git a/base/metrics/statistics_recorder.cc b/base/metrics/statistics_recorder.cc
index fb069a5cdac94c619a16f8c9350587e12c219c65..85408e1fa496dec8dae7574213a3f3b21a1b123d 100644
--- a/base/metrics/statistics_recorder.cc
+++ b/base/metrics/statistics_recorder.cc
@@ -14,9 +14,6 @@
 #include "base/synchronization/lock.h"
 #include "base/values.h"
 
-using std::list;
-using std::string;
-
 namespace {
 // Initialize histogram statistics gathering system.
 base::LazyInstance<base::StatisticsRecorder>::Leaky g_statistics_recorder_ =
@@ -59,7 +56,7 @@ HistogramBase* StatisticsRecorder::RegisterOrDeleteDuplicate(
     if (histograms_ == NULL) {
       histogram_to_return = histogram;
     } else {
-      const string& name = histogram->histogram_name();
+      const std::string& name = histogram->histogram_name();
       HistogramMap::iterator it = histograms_->find(name);
       if (histograms_->end() == it) {
         (*histograms_)[name] = histogram;
@@ -96,22 +93,18 @@ const BucketRanges* StatisticsRecorder::RegisterOrDeleteDuplicateRanges(
     return ranges;
   }
 
-  list<const BucketRanges*>* checksum_matching_list;
+  std::list<const BucketRanges*>* checksum_matching_list;
   RangesMap::iterator ranges_it = ranges_->find(ranges->checksum());
   if (ranges_->end() == ranges_it) {
     // Add a new matching list to map.
-    checksum_matching_list = new list<const BucketRanges*>();
+    checksum_matching_list = new std::list<const BucketRanges*>();
     ANNOTATE_LEAKING_OBJECT_PTR(checksum_matching_list);
     (*ranges_)[ranges->checksum()] = checksum_matching_list;
   } else {
     checksum_matching_list = ranges_it->second;
   }
 
-  list<const BucketRanges*>::iterator checksum_matching_list_it;
-  for (checksum_matching_list_it = checksum_matching_list->begin();
-       checksum_matching_list_it != checksum_matching_list->end();
-       ++checksum_matching_list_it) {
-    const BucketRanges* existing_ranges = *checksum_matching_list_it;
+  for (const BucketRanges* existing_ranges : *checksum_matching_list) {
     if (existing_ranges->Equals(ranges)) {
       if (existing_ranges == ranges) {
         return ranges;
@@ -135,10 +128,8 @@ void StatisticsRecorder::WriteHTMLGraph(const std::string& query,
 
   Histograms snapshot;
   GetSnapshot(query, &snapshot);
-  for (Histograms::iterator it = snapshot.begin();
-       it != snapshot.end();
-       ++it) {
-    (*it)->WriteHTMLGraph(output);
+  for (const HistogramBase* histogram : snapshot) {
+    histogram->WriteHTMLGraph(output);
     output->append("<br><hr><br>");
   }
 }
@@ -155,10 +146,8 @@ void StatisticsRecorder::WriteGraph(const std::string& query,
 
   Histograms snapshot;
   GetSnapshot(query, &snapshot);
-  for (Histograms::iterator it = snapshot.begin();
-       it != snapshot.end();
-       ++it) {
-    (*it)->WriteAscii(output);
+  for (const HistogramBase* histogram : snapshot) {
+    histogram->WriteAscii(output);
     output->append("\n");
   }
 }
@@ -179,14 +168,13 @@ std::string StatisticsRecorder::ToJSON(const std::string& query) {
   GetSnapshot(query, &snapshot);
   output += "\"histograms\":[";
   bool first_histogram = true;
-  for (Histograms::const_iterator it = snapshot.begin(); it != snapshot.end();
-       ++it) {
+  for (const HistogramBase* histogram : snapshot) {
     if (first_histogram)
       first_histogram = false;
     else
       output += ",";
     std::string json;
-    (*it)->WriteJSON(&json);
+    histogram->WriteJSON(&json);
     output += json;
   }
   output += "]}";
@@ -201,11 +189,9 @@ void StatisticsRecorder::GetHistograms(Histograms* output) {
   if (histograms_ == NULL)
     return;
 
-  for (HistogramMap::iterator it = histograms_->begin();
-       histograms_->end() != it;
-       ++it) {
-    DCHECK_EQ(it->first, it->second->histogram_name());
-    output->push_back(it->second);
+  for (const auto& entry : *histograms_) {
+    DCHECK_EQ(entry.first, entry.second->histogram_name());
+    output->push_back(entry.second);
   }
 }
 
@@ -218,15 +204,9 @@ void StatisticsRecorder::GetBucketRanges(
   if (ranges_ == NULL)
     return;
 
-  for (RangesMap::iterator it = ranges_->begin();
-       ranges_->end() != it;
-       ++it) {
-    list<const BucketRanges*>* ranges_list = it->second;
-    list<const BucketRanges*>::iterator ranges_list_it;
-    for (ranges_list_it = ranges_list->begin();
-         ranges_list_it != ranges_list->end();
-         ++ranges_list_it) {
-      output->push_back(*ranges_list_it);
+  for (const auto& entry : *ranges_) {
+    for (const auto& range_entry : *entry.second) {
+      output->push_back(range_entry);
     }
   }
 }
@@ -254,11 +234,9 @@ void StatisticsRecorder::GetSnapshot(const std::string& query,
   if (histograms_ == NULL)
     return;
 
-  for (HistogramMap::iterator it = histograms_->begin();
-       histograms_->end() != it;
-       ++it) {
-    if (it->first.find(query) != std::string::npos)
-      snapshot->push_back(it->second);
+  for (const auto& entry : *histograms_) {
+    if (entry.first.find(query) != std::string::npos)
+      snapshot->push_back(entry.second);
   }
 }
 
@@ -286,7 +264,7 @@ StatisticsRecorder::StatisticsRecorder() {
 
 // static
 void StatisticsRecorder::DumpHistogramsToVlog(void* instance) {
-  string output;
+  std::string output;
   StatisticsRecorder::WriteGraph(std::string(), &output);
   VLOG(1) << output;
 }