Add V8 heap statistics in a time-line manner in tracing.

content/renderer/v8_heap_statistics_collector_impl.h

Index: content/renderer/v8_heap_statistics_collector_impl.h
diff --git a/content/renderer/v8_heap_statistics_collector_impl.h b/content/renderer/v8_heap_statistics_collector_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..2f250f51e038717b13b9cf54ac0ad047a7d2eb9e
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+++ b/content/renderer/v8_heap_statistics_collector_impl.h
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+// Copyright 2014 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 CONTENT_RENDERER_V8_HEAP_STATISTICS_COLLECTOR_IMPL_H_
+#define CONTENT_RENDERER_V8_HEAP_STATISTICS_COLLECTOR_IMPL_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/task_runner.h"
+#include "content/public/renderer/v8_heap_statistics_collector.h"
+
+namespace content {
+
+class V8HeapStatisticsCollectorImpl : public V8HeapStatisticsCollector {
+ public:
+  static V8HeapStatisticsCollector* Instance();
+
+  V8HeapStatisticsCollectorImpl();
+
+  // V8ValueConverter implementation.
+  virtual bool InitiateCollection(const ResultCallback&) OVERRIDE;
+
+ private:
+  virtual ~V8HeapStatisticsCollectorImpl();
+  void CollectOnWorkerThread(scoped_refptr<base::TaskRunner> master,
+                             int round_id);
+  void ReceiveStats(int round_id, size_t total_size, size_t used_size);
+  void SendStatsToCallback(int round_id);
+
+  Statistics pending_stats_;
+  int workers_to_go_;
+  int round_id_;
+  scoped_ptr<ResultCallback> pending_result_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(V8HeapStatisticsCollectorImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_V8_HEAP_STATISTICS_COLLECTOR_IMPL_H_