Have a Page's MemoryPurgeController be a separate allocation also.

Source/core/page/Page.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 14 matching lines @@
 #include "core/dom/ViewportDescription.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/OriginsUsingFeatures.h"
 #include "core/frame/SettingsDelegate.h"
 #include "core/frame/UseCounter.h"
 #include "core/page/Page.h"
 #include "core/page/PageAnimator.h"
 #include "core/page/PageLifecycleNotifier.h"
 #include "core/page/PageLifecycleObserver.h"
 #include "core/page/PageVisibilityState.h"
-#include "platform/MemoryPurgeController.h"
 #include "platform/Supplementable.h"
 #include "platform/geometry/LayoutRect.h"
 #include "platform/geometry/Region.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 #include "wtf/HashSet.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class AutoscrollController;
 class ChromeClient;
 class ClientRectList;
 class CompositedDisplayList;
 class ContextMenuClient;
 class ContextMenuController;
 class Document;
 class DragCaretController;
 class DragClient;
 class DragController;
 class EditorClient;
 class FocusController;
 class Frame;
 class FrameHost;
+class MemoryPurgeController;
 class PluginData;
 class PointerLockController;
 class ScrollingCoordinator;
 class Settings;
 class SpellCheckerClient;
 class UndoStack;
 class ValidationMessageClient;
 
 typedef uint64_t LinkHash;
 
@@ skipping 127 matching lines @@
 
     void didCommitLoad(LocalFrame*);
 
     void acceptLanguagesChanged();
 
     void setCompositedDisplayList(PassOwnPtr<CompositedDisplayList>);
     CompositedDisplayList* compositedDisplayListForTesting();
 
     static void networkStateChanged(bool online);
 
-    MemoryPurgeController& memoryPurgeController() { return m_memoryPurgeController; }
+    MemoryPurgeController& memoryPurgeController();
 
     DECLARE_TRACE();
     void willBeDestroyed();
 
 private:
     void initGroup();
 
     void setTimerAlignmentInterval(double);
 
     void setNeedsLayoutInAllFrames();
@@ skipping 51 matching lines @@
 #if ENABLE(ASSERT)
     bool m_isPainting;
 #endif
 
     WillBeHeapHashSet<RawPtrWillBeWeakMember<MultisamplingChangedObserver>> m_multisamplingChangedObservers;
 
     // A pointer to all the interfaces provided to in-process Frames for this Page.
     // FIXME: Most of the members of Page should move onto FrameHost.
     OwnPtrWillBeMember<FrameHost> m_frameHost;
 
-    MemoryPurgeController m_memoryPurgeController;
+    OwnPtrWillBeMember<MemoryPurgeController> m_memoryPurgeController;
 };
 
 extern template class CORE_EXTERN_TEMPLATE_EXPORT WillBeHeapSupplement<Page>;
 
 } // namespace blink
 
 #endif // Page_h