Replace CJS_Runtime::Observer with CFX_Runtime<CJS_Runtime>::Observer

fpdfsdk/javascript/cjs_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_JAVASCRIPT_CJS_RUNTIME_H_
 #define FPDFSDK_JAVASCRIPT_CJS_RUNTIME_H_
 
 #include <map>
 #include <memory>
 #include <set>
 #include <utility>
 #include <vector>
 
+#include "core/fxcrt/include/cfx_observable.h"
 #include "core/fxcrt/include/fx_basic.h"
 #include "fpdfsdk/javascript/JS_EventHandler.h"
 #include "fpdfsdk/javascript/ijs_runtime.h"
 #include "fxjs/include/fxjs_v8.h"
 
 class CJS_Context;
 
-class CJS_Runtime : public IJS_Runtime, public CFXJS_Engine {
+class CJS_Runtime : public IJS_Runtime,
+                    public CFXJS_Engine,
+                    public CFX_Observable<CJS_Runtime> {
  public:
-  class Observer {
-   public:
-    virtual void OnDestroyed() = 0;
-
-   protected:
-    virtual ~Observer() {}
-  };
-
   using FieldEvent = std::pair<CFX_WideString, JS_EVENT_T>;
 
   static CJS_Runtime* FromContext(const IJS_Context* cc);
   static CJS_Runtime* CurrentRuntimeFromIsolate(v8::Isolate* pIsolate);
 
   explicit CJS_Runtime(CPDFDoc_Environment* pApp);
   ~CJS_Runtime() override;
 
   // IJS_Runtime
   IJS_Context* NewContext() override;
@@ skipping 14 matching lines @@
   void EndBlock() { m_bBlocking = FALSE; }
   FX_BOOL IsBlocking() const { return m_bBlocking; }
 
 #ifdef PDF_ENABLE_XFA
   FX_BOOL GetValueByName(const CFX_ByteStringC& utf8Name,
                          CFXJSE_Value* pValue) override;
   FX_BOOL SetValueByName(const CFX_ByteStringC& utf8Name,
                          CFXJSE_Value* pValue) override;
 #endif  // PDF_ENABLE_XFA
 
-  void AddObserver(Observer* observer);
-  void RemoveObserver(Observer* observer);
-
  private:
   void DefineJSObjects();
 
   std::vector<std::unique_ptr<CJS_Context>> m_ContextArray;
   CPDFDoc_Environment* const m_pApp;
   CPDFSDK_Document* m_pDocument;
   bool m_bBlocking;
   bool m_isolateManaged;
   std::set<FieldEvent> m_FieldEventSet;
-  std::set<Observer*> m_observers;
 };
 
 #endif  // FPDFSDK_JAVASCRIPT_CJS_RUNTIME_H_