metrics: Add leak detector controller in Chrome OS metrics system

components/metrics/leak_detector/leak_detector.cc

Index: components/metrics/leak_detector/leak_detector.cc
diff --git a/components/metrics/leak_detector/leak_detector.cc b/components/metrics/leak_detector/leak_detector.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b3e5ed0786946aad6524390e17be1a07c23199d3
--- /dev/null
+++ b/components/metrics/leak_detector/leak_detector.cc
@@ -0,0 +1,58 @@
+// 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.
+
+#include "components/metrics/leak_detector/leak_detector.h"
+
+#include <algorithm>
+
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;

[Alexei Svitkine (slow), 2016/02/23 01:23:35]

Nit: Just use the content:: prefix in the code directly and remove this.

[Simon Que, 2016/02/23 02:38:29]

Done.

+
+namespace metrics {
+
+const base::Feature kEnableRuntimeMemoryLeakDetector = {

[Alexei Svitkine (slow), 2016/02/23 01:23:35]

Nit: No =

[Simon Que, 2016/02/23 02:38:29]

Done.

+    "enable-runtime-memory-leak-detector", base::FEATURE_DISABLED_BY_DEFAULT};

[Alexei Svitkine (slow), 2016/02/23 01:23:35]

Nit: "RuntimeMemoryLeakDetector"

Given you're not checking for this feature under components/, suggest putting it
in chrome/ - for example in chrome_features.cc.

[Simon Que, 2016/02/23 02:38:29]

Done.

+
+LeakDetector::LeakReport::LeakReport() {}
+
+LeakDetector::LeakReport::~LeakReport() {}
+
+LeakDetector::LeakDetector(float sampling_rate,
+                           int max_stack_depth,
+                           uint64_t analysis_interval_bytes,
+                           int size_suspicion_threshold,
+                           int call_stack_suspicion_threshold)
+  : weak_factory_(this) {}
+
+LeakDetector::LeakDetector() : LeakDetector(1.0f, 4, 32 * 1024 * 1024, 4, 4) {}
+
+LeakDetector::~LeakDetector() {}
+
+void LeakDetector::AddObserver(Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observers_.AddObserver(observer);
+}
+
+void LeakDetector::RemoveObserver(Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observers_.RemoveObserver(observer);
+}
+
+void LeakDetector::NotifyObservers(const std::vector<LeakReport>& reports) {
+  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    BrowserThread::PostTask(BrowserThread::UI,
+                            FROM_HERE,
+                            base::Bind(&LeakDetector::NotifyObservers,
+                                       weak_factory_.GetWeakPtr(),
+                                       reports));
+    return;
+  }
+
+  for (const LeakReport& report : reports) {
+    FOR_EACH_OBSERVER(Observer, observers_, OnLeakFound(report));
+  }
+}
+
+}  // namespace metrics