Make code compile with clang_use_chrome_plugin (part IV)

fpdfsdk/javascript/JS_Object.h

Index: fpdfsdk/javascript/JS_Object.h
diff --git a/fpdfsdk/javascript/JS_Object.h b/fpdfsdk/javascript/JS_Object.h
index 49c078d927ab9b549c417201ea66e864b7f11299..908645ce335883d14b93adf69dc912977674c2c5 100644
--- a/fpdfsdk/javascript/JS_Object.h
+++ b/fpdfsdk/javascript/JS_Object.h
@@ -46,11 +46,11 @@ class CJS_Object {
   void MakeWeak();
   void Dispose();
 
-  virtual FX_BOOL IsType(const FX_CHAR* sClassName) { return TRUE; }
-  virtual CFX_ByteString GetClassName() { return ""; }
+  virtual FX_BOOL IsType(const FX_CHAR* sClassName);
+  virtual CFX_ByteString GetClassName();
 
-  virtual void InitInstance(IJS_Runtime* pIRuntime) {}
-  virtual void ExitInstance() {}
+  virtual void InitInstance(IJS_Runtime* pIRuntime);
+  virtual void ExitInstance();
 
   v8::Local<v8::Object> ToV8Object() { return m_pV8Object.Get(m_pIsolate); }