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

fpdfsdk/javascript/cjs_runtime.cpp

Index: fpdfsdk/javascript/cjs_runtime.cpp
diff --git a/fpdfsdk/javascript/cjs_runtime.cpp b/fpdfsdk/javascript/cjs_runtime.cpp
index b12a3f5eeb278f77693b9dd825859acb5bc0c26e..67d45d5e4a6b6e7eeb63e470f1605d361c0c9443 100644
--- a/fpdfsdk/javascript/cjs_runtime.cpp
+++ b/fpdfsdk/javascript/cjs_runtime.cpp
@@ -124,9 +124,7 @@ CJS_Runtime::CJS_Runtime(CPDFDoc_Environment* pApp)
 }
 
 CJS_Runtime::~CJS_Runtime() {
-  for (auto* obs : m_observers)
-    obs->OnDestroyed();
-
+  NotifyObservers();
   ReleaseEngine();
   if (m_isolateManaged) {
     GetIsolate()->Dispose();
@@ -255,16 +253,6 @@ void CJS_Runtime::RemoveEventFromSet(const FieldEvent& event) {
   m_FieldEventSet.erase(event);
 }
 
-void CJS_Runtime::AddObserver(Observer* observer) {
-  ASSERT(!pdfium::ContainsKey(m_observers, observer));
-  m_observers.insert(observer);
-}
-
-void CJS_Runtime::RemoveObserver(Observer* observer) {
-  ASSERT(pdfium::ContainsKey(m_observers, observer));
-  m_observers.erase(observer);
-}
-
 #ifdef PDF_ENABLE_XFA
 CFX_WideString ChangeObjName(const CFX_WideString& str) {
   CFX_WideString sRet = str;