metrics: Add leak detector controller in Chrome OS metrics system

chrome/browser/metrics/leak_detector_controller.h

+// Copyright 2016 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.
+
+#ifndef CHROME_BROWSER_METRICS_LEAK_DETECTOR_CONTROLLER_H_
+#define CHROME_BROWSER_METRICS_LEAK_DETECTOR_CONTROLLER_H_
+
+#include <vector>
+
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "components/metrics/leak_detector/leak_detector.h"
+#include "components/metrics/proto/memory_leak_report.pb.h"
+
+namespace metrics {
+
+// This class initializes the LeakDetector on the browser process and registers
+// itself to be notified of leak reports.
+class LeakDetectorController : public LeakDetector::Observer {
+ public:
+  LeakDetectorController();
+  ~LeakDetectorController() override;
+
+  // Retrieves all reports in |stored_reports_|, moving them to |*reports|.
+  // |stored_reports_| is empty afterwards.
+  void GetLeakReports(std::vector<MemoryLeakReportProto>* reports);
+
+ protected:
+  // LeakDetector::Observer:
+  void OnLeakFound(const LeakDetector::LeakReport& report) override;

[Will Harris, 2016/02/20 08:54:05]

why is this protected and not public, normally interface overrides are public.

[Simon Que, 2016/02/22 23:26:18]

In an earlier comment, Alexei suggested it be made private, presumably because
it's not being called directly from anywhere except the unit test.

But I can make this public if you think this is the more proper way.

+
+ private:
+  // Leak detector interface object.
+  LeakDetector detector_;
+
+  // All leak reports received through OnLeakFound() are stored in protobuf
+  // format.
+  std::vector<MemoryLeakReportProto> stored_reports_;
+
+  // For thread safety.
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(LeakDetectorController);
+};
+
+}  // namespace metrics
+
+#endif  // CHROME_BROWSER_METRICS_LEAK_DETECTOR_CONTROLLER_H_