Report histogram creation results.

base/metrics/statistics_recorder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/metrics/statistics_recorder.h"
 
 #include "base/at_exit.h"
 #include "base/debug/leak_annotations.h"
 #include "base/json/string_escape.h"
 #include "base/logging.h"
@@ skipping 49 matching lines @@
     if (!include_persistent_ && (iter_->second->flags() &
                                  HistogramBase::kIsPersistent)) {
       continue;
     }
     break;
   }
 
   return *this;
 }
 
+StatisticsRecorder::~StatisticsRecorder() {
+  DCHECK(histograms_ && ranges_ && lock_);

[Alexei Svitkine (slow), 2016/03/07 21:14:51]

Nit: Not sure why I missed that in the previous CL, but these should be separate
DCHECKs so that if it fails, it's clear which one it is.

[bcwhite, 2016/03/07 22:20:41]

Done.

+
+  // Global clean up.
+  Reset();
+}
+
 // static
 void StatisticsRecorder::Initialize() {
   // Ensure that an instance of the StatisticsRecorder object is created.
   g_statistics_recorder_.Get();
 }
 
 // static
 bool StatisticsRecorder::IsActive() {
   if (lock_ == NULL)
     return false;
@@ skipping 282 matching lines @@
   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();
 }
 
 // static
+size_t StatisticsRecorder::GetHistogramCount() {
+  if (!lock_)
+    return 0;
+
+  base::AutoLock auto_lock(*lock_);
+  if (!histograms_)
+    return 0;
+  return histograms_->size();
+}
+
+// static
 void StatisticsRecorder::ResetForTesting() {
   // Just call the private version that is used also by the destructor.
   Reset();
 }
 
 // static
 void StatisticsRecorder::ForgetHistogramForTesting(base::StringPiece name) {
   if (histograms_)
     histograms_->erase(HashMetricName(name.as_string()));
 }
@@ skipping 14 matching lines @@
   }
   base::AutoLock auto_lock(*lock_);
   histograms_ = new HistogramMap;
   callbacks_ = new CallbackMap;
   ranges_ = new RangesMap;
 
   if (VLOG_IS_ON(1))
     AtExitManager::RegisterCallback(&DumpHistogramsToVlog, this);
 }
 
-StatisticsRecorder::~StatisticsRecorder() {
-  DCHECK(histograms_ && ranges_ && lock_);
-
-  // Global clean up.
-  Reset();
-}
-
 // static
 void StatisticsRecorder::Reset() {
   // If there's no lock then there is nothing to reset.
   if (!lock_)
     return;
 
   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
@@ skipping 21 matching lines @@
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
 StatisticsRecorder::CallbackMap* StatisticsRecorder::callbacks_ = NULL;
 // static
 StatisticsRecorder::RangesMap* StatisticsRecorder::ranges_ = NULL;
 // static
 base::Lock* StatisticsRecorder::lock_ = NULL;
 
 }  // namespace base