components/metrics: Add runtime memory leak detector

components/metrics/leak_detector/leak_detector_value_type.h

Index: components/metrics/leak_detector/leak_detector_value_type.h
diff --git a/components/metrics/leak_detector/leak_detector_value_type.h b/components/metrics/leak_detector/leak_detector_value_type.h
new file mode 100644
index 0000000000000000000000000000000000000000..8f5877bc8e87ad31eec6670a36468d91e36655ec
--- /dev/null
+++ b/components/metrics/leak_detector/leak_detector_value_type.h
@@ -0,0 +1,78 @@
+// Copyright 2015 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 COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_DETECTOR_VALUE_TYPE_
+#define COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_DETECTOR_VALUE_TYPE_
+
+#include <stdint.h>
+
+namespace leak_detector {
+
+// Used for tracking unique call stacks.
+class CallStack;
+
+class LeakDetectorValueType {
+ public:
+  // Supported types.
+  enum Type {
+    kNone,
+    kSize,
+    kCallStack,
+  };
+
+  LeakDetectorValueType() : type_(kNone) {}
+  explicit LeakDetectorValueType(uint32_t size)
+      : type_(kSize), size_(size) {}
+  explicit LeakDetectorValueType(const CallStack* call_stack)
+      : type_(kCallStack), call_stack_(call_stack) {}
+
+  // Accessors.
+  Type type() const {
+    return type_;
+  }
+  uint32_t size() const {
+    return size_;
+  }
+  const CallStack* call_stack() const {
+    return call_stack_;
+  }
+
+  // Comparators.
+  bool operator == (const LeakDetectorValueType& other) const {
+    if (type_ != other.type_)
+      return false;
+
+    switch(type_) {
+    case kSize:
+      return size_ == other.size_;
+    case kCallStack:
+      return call_stack_ == other.call_stack_;
+    default:
+      return false;
+    }
+  };
+  bool operator < (const LeakDetectorValueType& other) const {
+    if (type_ < other.type_)
+      return true;
+
+    switch(type_) {
+    case kSize:
+      return size_ < other.size_;
+    case kCallStack:
+      return call_stack_ < other.call_stack_;
+    default:
+      return false;
+    }
+  };
+
+ private:
+  Type type_;
+
+  uint32_t size_;
+  const CallStack* call_stack_;
+};
+
+}  // namespace leak_detector
+
+#endif  // COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_DETECTOR_VALUE_TYPE_