Make RenderThreadImpl a client of memory coordinator

third_party/WebKit/Source/platform/MemoryCoordinator.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 MemoryCoordinator_h
 #define MemoryCoordinator_h
 
 #include "platform/PlatformExport.h"
 #include "platform/heap/Handle.h"
 #include "public/platform/WebMemoryPressureLevel.h"
+#include "public/platform/WebMemoryState.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT MemoryCoordinatorClient : public GarbageCollectedMixin {
  public:
   virtual ~MemoryCoordinatorClient() {}
 
   // Called when MemoryCoordinator is asked to prepare for suspending
   // the renderer. Clients should purge discardable memory as much as
   // possible.
   virtual void prepareToSuspend() {}
 
   // TODO(bashi): Deprecating. Remove this when MemoryPressureListener is
   // gone.
   virtual void onMemoryPressure(WebMemoryPressureLevel) {}
+
+  virtual void onMemoryStateChange(MemoryState) {}
 };
 
 // MemoryCoordinator listens to some events which could be opportunities
 // for reducing memory consumption and notifies its clients.
 class PLATFORM_EXPORT MemoryCoordinator final
     : public GarbageCollected<MemoryCoordinator> {
   WTF_MAKE_NONCOPYABLE(MemoryCoordinator);
 
  public:
   static MemoryCoordinator& instance();
 
   void registerClient(MemoryCoordinatorClient*);
   void unregisterClient(MemoryCoordinatorClient*);
 
   void prepareToSuspend();
 
   // TODO(bashi): Deprecating. Remove this when MemoryPressureListener is
   // gone.
   void onMemoryPressure(WebMemoryPressureLevel);
 
+  void onMemoryStateChange(MemoryState);
+
   DECLARE_TRACE();
 
  private:
   MemoryCoordinator();
 
+  void clearMemory();
+
   HeapHashSet<WeakMember<MemoryCoordinatorClient>> m_clients;
 };
 
 }  // namespace blink
 
 #endif  // MemoryCoordinator_h