[RF] Make RooArgProxy::isValueServer() and isShapeServer() public

There is no reason to hide these member functions from the user, which
are `const` getters to values that the user was setting themselves to
begin with.

Author: guitargeek

roofit/roofitcore/inc/RooArgProxy.h

@@ -50,19 +50,6 @@ class RooArgProxy : public TNamed, public RooAbsProxy  {
   /// Returns the owner of this proxy.
   RooAbsArg* owner() const { return _owner; }
 
-protected:
-
-  friend class RooSimultaneous ;
-  RooAbsArg* _owner ;       ///< Pointer to owner of proxy
-  RooAbsArg* _arg ;         ///< Pointer to content of proxy
-
-  bool _valueServer ;     ///< If true contents is value server of owner
-  bool _shapeServer ;     ///< If true contents is shape server of owner
-  bool _isFund ;          ///< If true proxy contains an lvalue
-  bool _ownArg ;          ///< If true proxy owns contents
-
-  friend class RooAbsArg ;
-
   /// Returns true of contents is value server of owner
   inline bool isValueServer() const {
     return _valueServer ;
@@ -71,10 +58,21 @@ class RooArgProxy : public TNamed, public RooAbsProxy  {
   inline bool isShapeServer() const {
     return _shapeServer ;
   }
+
+protected:
+
   bool changePointer(const RooAbsCollection& newServerSet, bool nameChange=false, bool factoryInitMode=false) override ;
 
   virtual void changeDataSet(const RooArgSet* newNormSet) ;
 
+  RooAbsArg* _owner = nullptr;  ///< Pointer to owner of proxy
+  RooAbsArg* _arg = nullptr;    ///< Pointer to content of proxy
+
+  bool _valueServer = false;    ///< If true contents is value server of owner
+  bool _shapeServer = false;    ///< If true contents is shape server of owner
+  bool _isFund = true;          ///< If true proxy contains an lvalue
+  bool _ownArg = false;         ///< If true proxy owns contents
+
   ClassDefOverride(RooArgProxy,1) // Abstract proxy for RooAbsArg objects
 };