Remove CLASSHASH defines in favour of an enum class.

xfa/fwl/basewidget/fwl_formproxyimp.h

Index: xfa/fwl/basewidget/fwl_formproxyimp.h
diff --git a/xfa/fwl/basewidget/fwl_formproxyimp.h b/xfa/fwl/basewidget/fwl_formproxyimp.h
index 4e5e8075078a99e0cb4d98e50a304ff47612d3ae..55e8c398c641bc24e816ccf27f556a6eada101f6 100644
--- a/xfa/fwl/basewidget/fwl_formproxyimp.h
+++ b/xfa/fwl/basewidget/fwl_formproxyimp.h
@@ -17,19 +17,22 @@ class CFWL_FormProxyImp : public CFWL_FormImp {
  public:
   CFWL_FormProxyImp(const CFWL_WidgetImpProperties& properties,
                     IFWL_Widget* pOuter);
-  ~CFWL_FormProxyImp();
-  virtual FWL_ERR GetClassName(CFX_WideString& wsClass) const;
-  virtual uint32_t GetClassID() const;
-  virtual FX_BOOL IsInstance(const CFX_WideStringC& wsClass) const;
-  virtual FWL_ERR Initialize();
-  virtual FWL_ERR Finalize();
-  virtual FWL_ERR Update();
-  virtual FWL_ERR DrawWidget(CFX_Graphics* pGraphics,
-                             const CFX_Matrix* pMatrix = NULL);
+  ~CFWL_FormProxyImp() override;
+
+  // CFWL_WidgetImp
+  FWL_ERR GetClassName(CFX_WideString& wsClass) const override;
+  FWL_Type GetClassID() const override { return FWL_Type::FormProxy; }
+  FX_BOOL IsInstance(const CFX_WideStringC& wsClass) const override;
+  FWL_ERR Initialize() override;
+  FWL_ERR Finalize() override;
+  FWL_ERR Update() override;
+  FWL_ERR DrawWidget(CFX_Graphics* pGraphics,
+                     const CFX_Matrix* pMatrix = nullptr) override;
 
  protected:
   friend class CFWL_FormProxyImpDelegate;
 };
+
 class CFWL_FormProxyImpDelegate : public CFWL_WidgetImpDelegate {
  public:
   CFWL_FormProxyImpDelegate(CFWL_FormProxyImp* pOwner);