Move platform/MemoryPurgeController -> core/dom/MemoryCoordinator

third_party/WebKit/Source/platform/MemoryPurgeController.h

-// 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 MemoryPurgeController_h
-#define MemoryPurgeController_h
-
-#include "platform/PlatformExport.h"
-#include "platform/Timer.h"
-#include "platform/heap/Handle.h"
-#include "public/platform/WebMemoryPressureLevel.h"
-
-namespace blink {
-
-enum class DeviceKind {
-    NotSpecified,
-    LowEnd,
-};
-
-// Classes which have discardable/reducible memory can implement this
-// interface to be informed when they should reduce memory consumption.
-// MemoryPurgeController assumes that subclasses of MemoryPurgeClient are
-// WillBes.
-class PLATFORM_EXPORT MemoryPurgeClient : public GarbageCollectedMixin {
-public:
-    virtual ~MemoryPurgeClient() { }
-
-    // MemoryPurgeController invokes this callback when a memory purge event
-    // has occurred.
-    virtual void purgeMemory(DeviceKind) = 0;
-
-    DECLARE_VIRTUAL_TRACE();
-};
-
-// MemoryPurgeController listens to some events which could be opportunities
-// for reducing memory consumption and notifies its clients.
-// Since we want to control memory per tab, MemoryPurgeController is owned by
-// Page.
-class PLATFORM_EXPORT MemoryPurgeController final : public GarbageCollected<MemoryPurgeController> {
-    WTF_MAKE_NONCOPYABLE(MemoryPurgeController);
-public:
-    static void onMemoryPressure(WebMemoryPressureLevel);
-
-    static MemoryPurgeController* create()
-    {
-        return new MemoryPurgeController;
-    }
-
-    void registerClient(MemoryPurgeClient* client)
-    {
-        ASSERT(isMainThread());
-        ASSERT(client);
-        ASSERT(!m_clients.contains(client));
-        m_clients.add(client);
-    }
-
-    void unregisterClient(MemoryPurgeClient* client)
-    {
-        // Don't assert m_clients.contains() so that clients can unregister
-        // unconditionally.
-        ASSERT(isMainThread());
-        m_clients.remove(client);
-    }
-
-    void purgeMemory();
-
-    DECLARE_TRACE();
-
-private:
-    MemoryPurgeController();
-
-    HeapHashSet<WeakMember<MemoryPurgeClient>> m_clients;
-    DeviceKind m_deviceKind;
-};
-
-} // namespace blink
-
-#endif // MemoryPurgeController_h