CJS_Timer should observe CJS_Runtime destruction.

fpdfsdk/include/javascript/JS_Runtime.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef FPDFSDK_INCLUDE_JAVASCRIPT_JS_RUNTIME_H_
 #define FPDFSDK_INCLUDE_JAVASCRIPT_JS_RUNTIME_H_
 
 #include <set>
 #include <utility>
 
 #include "../../../core/include/fxcrt/fx_basic.h"
 #include "../jsapi/fxjs_v8.h"
 #include "IJavaScript.h"
 #include "JS_EventHandler.h"
 
 class CJS_Context;
 
 class CJS_Runtime : public IFXJS_Runtime {
  public:
+  class Observer {
+   public:
+    virtual void OnDestroyed() = 0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
   using FieldEvent = std::pair<CFX_WideString, JS_EVENT_T>;
 
   explicit CJS_Runtime(CPDFDoc_Environment* pApp);
   ~CJS_Runtime() override;
 
   // IFXJS_Runtime
   IFXJS_Context* NewContext() override;
   void ReleaseContext(IFXJS_Context* pContext) override;
   IFXJS_Context* GetCurrentContext() override;
   void SetReaderDocument(CPDFSDK_Document* pReaderDoc) override;
   CPDFSDK_Document* GetReaderDocument() override { return m_pDocument; }
 
   CPDFDoc_Environment* GetReaderApp() const { return m_pApp; }
 
   // Returns true if the event isn't already found in the set.
   bool AddEventToSet(const FieldEvent& event);
   void RemoveEventFromSet(const FieldEvent& event);
 
   void BeginBlock() { m_bBlocking = TRUE; }
   void EndBlock() { m_bBlocking = FALSE; }
   FX_BOOL IsBlocking() const { return m_bBlocking; }
 
   v8::Isolate* GetIsolate() const { return m_isolate; }
   v8::Local<v8::Context> NewJSContext();
 
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
  private:
   void DefineJSObjects();
 
   CFX_ArrayTemplate<CJS_Context*> m_ContextArray;
   CPDFDoc_Environment* m_pApp;
   CPDFSDK_Document* m_pDocument;
   FX_BOOL m_bBlocking;
   std::set<FieldEvent> m_FieldEventSet;
   v8::Isolate* m_isolate;
   bool m_isolateManaged;
   v8::Global<v8::Context> m_context;
+  std::set<Observer*> m_observers;
 };
 
 #endif  // FPDFSDK_INCLUDE_JAVASCRIPT_JS_RUNTIME_H_