Add MemoryCoordinatorImpl

content/browser/memory/memory_coordinator_impl.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 CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_IMPL_H_
+#define CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_IMPL_H_
+
+#include "base/memory/singleton.h"
+#include "base/time/time.h"
+#include "content/browser/memory/memory_coordinator.h"
+
+namespace content {
+
+class MemoryMonitor;
+struct MemoryCoordinatorSingletonTraits;
+
+class MemoryCoordinatorImpl : public MemoryCoordinator {
+ public:
+  explicit MemoryCoordinatorImpl(std::unique_ptr<MemoryMonitor> monitor);
+  ~MemoryCoordinatorImpl() override;
+
+ protected:
+  void OnChildAdded() override;
+  void OnChildRemoved() override;
+
+ private:
+  friend struct MemoryCoordinatorSingletonTraits;
+
+  // This struct holds some parameters to determine the global state.
+  struct Configuration {
+    int pressure_threshold_mb;
+    size_t num_children_until_suspended;
+    base::TimeDelta minimum_transition_period;
+  };
+
+  void UpdateState();
+  void NotifyStateToClients();
+  void NotifyStateToChildren();
+
+  using MemoryState = base::MemoryState;
+
+  std::unique_ptr<MemoryMonitor> memory_monitor_;
+  Configuration config_;
+  base::MemoryState current_state_ = MemoryState::NORMAL;
+  base::TimeTicks last_state_change_;
+
+  DISALLOW_COPY_AND_ASSIGN(MemoryCoordinatorImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEMORY_MEMORY_COORDINATOR_IMPL_H_