Low memory page navigation GC for low end devices

third_party/WebKit/Source/bindings/core/v8/WindowProxy.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 133 matching lines @@
 class WindowProxy : public GarbageCollectedFinalized<WindowProxy> {
  public:
   virtual ~WindowProxy();
 
   DECLARE_TRACE();
 
   void InitializeIfNeeded();
 
   void ClearForClose();
   void ClearForNavigation();
+  void ClearForSwap();
 
   CORE_EXPORT v8::Local<v8::Object> GlobalProxyIfNotDetached();
   v8::Local<v8::Object> ReleaseGlobalProxy();
   void SetGlobalProxy(v8::Local<v8::Object>);
 
   // TODO(dcheng): Temporarily exposed to avoid include cycles. Remove the need
   // for this and remove this getter.
   DOMWrapperWorld& World() { return *world_; }
 
   virtual bool IsLocal() const { return false; }
 
+  enum FrameReuseStatus { kFrameWillNotBeReused, kFrameWillBeReused };
+
  protected:
   // Lifecycle represents the following four states.
   //
   // * kContextIsUninitialized
   // We lazily initialize WindowProxies for performance reasons, and this state
   // is "to be initialized on demand". WindowProxy basically behaves the same as
   // |kContextIsInitialized| from a point of view of call sites.
   // - Possible next states: kContextIsInitialized
   // It's possible to detach the context's frame from the DOM or navigate to a
   // new page without initializing the WindowProxy, however, there is no
@@ skipping 45 matching lines @@
     // global).
     kGlobalObjectIsDetached,
     // The context's frame is detached from the DOM.
     kFrameIsDetached,
   };
 
   WindowProxy(v8::Isolate*, Frame&, RefPtr<DOMWrapperWorld>);
 
   virtual void Initialize() = 0;
 
-  virtual void DisposeContext(Lifecycle next_status) = 0;
+  virtual void DisposeContext(Lifecycle next_status, FrameReuseStatus) = 0;
 
   WARN_UNUSED_RESULT v8::Local<v8::Object> AssociateWithWrapper(
       DOMWindow*,
       const WrapperTypeInfo*,
       v8::Local<v8::Object> wrapper);
 
   v8::Isolate* GetIsolate() const { return isolate_; }
   Frame* GetFrame() const { return frame_.Get(); }
 
 #if DCHECK_IS_ON()
@@ skipping 19 matching lines @@
   Lifecycle lifecycle_;
 
   // TODO(dcheng): Remove this temporary code for debugging
   // https://crbug.com/728693.
   WTF::debug::StackTrace initialization_stack_;
 };
 
 }  // namespace blink
 
 #endif  // WindowProxy_h