Persist setup metrics and have Chrome report them during UMA upload.

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 375 matching lines @@
   histograms_ = new HistogramMap;
   callbacks_ = new CallbackMap;
   ranges_ = new RangesMap;
 
   if (VLOG_IS_ON(1))
     AtExitManager::RegisterCallback(&DumpHistogramsToVlog, this);
 }
 
 // static
 void StatisticsRecorder::ResetForTesting() {
-  if (histograms_) {
-    STLDeleteValues(histograms_);
-    delete histograms_;
-    histograms_= nullptr;
-  }
-  if (ranges_) {
-    for (auto& iter : *ranges_) {
-      STLDeleteElements(iter.second);
-      delete iter.second;
-    }
-    delete ranges_;
-    ranges_ = nullptr;
-  }
+  // This leaks a lot of objects but they've allready been annotated for such.

[grt (UTC plus 2), 2016/02/15 15:42:39]

"already"

[bcwhite, 2016/02/15 19:22:10]

Done.

+  // Deleting them isn't possible because there could be other pointers to
+  // them somewhere.
+  delete histograms_;
+  histograms_= nullptr;
+  delete ranges_;
+  ranges_ = nullptr;
   delete callbacks_;
   callbacks_ = nullptr;
 }
 
 // static
+void StatisticsRecorder::ForgetHistogramForTesting(const std::string& name) {
+  if (histograms_)
+    histograms_->erase(HashMetricName(name));
+}
+
+// static
 void StatisticsRecorder::DumpHistogramsToVlog(void* instance) {
   std::string output;
   StatisticsRecorder::WriteGraph(std::string(), &output);
   VLOG(1) << output;
 }
 
 StatisticsRecorder::~StatisticsRecorder() {
   DCHECK(histograms_ && ranges_ && lock_);
 
   // Clean up.
@@ skipping 18 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