Update //base to chromium 9659b08ea5a34f889dc4166217f438095ddc10d2

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 85408e1fa496dec8dae7574213a3f3b21a1b123d..87ffa3dbcd04e78a724a3bec71b650726bdce79c 100644
--- a/base/metrics/statistics_recorder.cc
+++ b/base/metrics/statistics_recorder.cc
@@ -10,6 +10,7 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
+#include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/lock.h"
 #include "base/values.h"
@@ -57,10 +58,19 @@ HistogramBase* StatisticsRecorder::RegisterOrDeleteDuplicate(
       histogram_to_return = histogram;
     } else {
       const std::string& name = histogram->histogram_name();
-      HistogramMap::iterator it = histograms_->find(name);
+      HistogramMap::iterator it = histograms_->find(HistogramNameRef(name));
       if (histograms_->end() == it) {
-        (*histograms_)[name] = histogram;
+        (*histograms_)[HistogramNameRef(name)] = histogram;
         ANNOTATE_LEAKING_OBJECT_PTR(histogram);  // see crbug.com/79322
+        // If there are callbacks for this histogram, we set the kCallbackExists
+        // flag.
+        auto callback_iterator = callbacks_->find(name);
+        if (callback_iterator != callbacks_->end()) {
+          if (!callback_iterator->second.is_null())
+            histogram->SetFlags(HistogramBase::kCallbackExists);
+          else
+            histogram->ClearFlags(HistogramBase::kCallbackExists);
+        }
         histogram_to_return = histogram;
       } else if (histogram == it->second) {
         // The histogram was registered before.
@@ -190,7 +200,7 @@ void StatisticsRecorder::GetHistograms(Histograms* output) {
     return;
 
   for (const auto& entry : *histograms_) {
-    DCHECK_EQ(entry.first, entry.second->histogram_name());
+    DCHECK_EQ(entry.first.name_, entry.second->histogram_name());
     output->push_back(entry.second);
   }
 }
@@ -219,12 +229,64 @@ HistogramBase* StatisticsRecorder::FindHistogram(const std::string& name) {
   if (histograms_ == NULL)
     return NULL;
 
-  HistogramMap::iterator it = histograms_->find(name);
+  HistogramMap::iterator it = histograms_->find(HistogramNameRef(name));
   if (histograms_->end() == it)
     return NULL;
   return it->second;
 }
 
+// static
+bool StatisticsRecorder::SetCallback(
+    const std::string& name,
+    const StatisticsRecorder::OnSampleCallback& cb) {
+  DCHECK(!cb.is_null());
+  if (lock_ == NULL)
+    return false;
+  base::AutoLock auto_lock(*lock_);
+  if (histograms_ == NULL)
+    return false;
+
+  if (ContainsKey(*callbacks_, name))
+    return false;
+  callbacks_->insert(std::make_pair(name, cb));
+
+  auto histogram_iterator = histograms_->find(HistogramNameRef(name));
+  if (histogram_iterator != histograms_->end())
+    histogram_iterator->second->SetFlags(HistogramBase::kCallbackExists);
+
+  return true;
+}
+
+// static
+void StatisticsRecorder::ClearCallback(const std::string& name) {
+  if (lock_ == NULL)
+    return;
+  base::AutoLock auto_lock(*lock_);
+  if (histograms_ == NULL)
+    return;
+
+  callbacks_->erase(name);
+
+  // We also clear the flag from the histogram (if it exists).
+  auto histogram_iterator = histograms_->find(HistogramNameRef(name));
+  if (histogram_iterator != histograms_->end())
+    histogram_iterator->second->ClearFlags(HistogramBase::kCallbackExists);
+}
+
+// static
+StatisticsRecorder::OnSampleCallback StatisticsRecorder::FindCallback(
+    const std::string& name) {
+  if (lock_ == NULL)
+    return OnSampleCallback();
+  base::AutoLock auto_lock(*lock_);
+  if (histograms_ == NULL)
+    return OnSampleCallback();
+
+  auto callback_iterator = callbacks_->find(name);
+  return callback_iterator != callbacks_->end() ? callback_iterator->second
+                                                : OnSampleCallback();
+}
+
 // private static
 void StatisticsRecorder::GetSnapshot(const std::string& query,
                                      Histograms* snapshot) {
@@ -235,7 +297,7 @@ void StatisticsRecorder::GetSnapshot(const std::string& query,
     return;
 
   for (const auto& entry : *histograms_) {
-    if (entry.first.find(query) != std::string::npos)
+    if (entry.first.name_.find(query) != std::string::npos)
       snapshot->push_back(entry.second);
   }
 }
@@ -256,6 +318,7 @@ StatisticsRecorder::StatisticsRecorder() {
   }
   base::AutoLock auto_lock(*lock_);
   histograms_ = new HistogramMap;
+  callbacks_ = new CallbackMap;
   ranges_ = new RangesMap;
 
   if (VLOG_IS_ON(1))
@@ -274,14 +337,17 @@ StatisticsRecorder::~StatisticsRecorder() {
 
   // Clean up.
   scoped_ptr<HistogramMap> histograms_deleter;
+  scoped_ptr<CallbackMap> callbacks_deleter;
   scoped_ptr<RangesMap> ranges_deleter;
   // We don't delete lock_ on purpose to avoid having to properly protect
   // against it going away after we checked for NULL in the static methods.
   {
     base::AutoLock auto_lock(*lock_);
     histograms_deleter.reset(histograms_);
+    callbacks_deleter.reset(callbacks_);
     ranges_deleter.reset(ranges_);
     histograms_ = NULL;
+    callbacks_ = NULL;
     ranges_ = NULL;
   }
   // We are going to leak the histograms and the ranges.
@@ -291,6 +357,8 @@ StatisticsRecorder::~StatisticsRecorder() {
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
+StatisticsRecorder::CallbackMap* StatisticsRecorder::callbacks_ = NULL;
+// static
 StatisticsRecorder::RangesMap* StatisticsRecorder::ranges_ = NULL;
 // static
 base::Lock* StatisticsRecorder::lock_ = NULL;