Change IFWL_Widget to store a single delegate.

xfa/fwl/core/ifwl_widget.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 XFA_FWL_CORE_IFWL_WIDGET_H_
 #define XFA_FWL_CORE_IFWL_WIDGET_H_
 
 #include <memory>
 
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_system.h"
+#include "third_party/base/ptr_util.h"
 #include "xfa/fwl/core/cfwl_event.h"
 #include "xfa/fwl/core/cfwl_themepart.h"
 #include "xfa/fwl/core/fwl_widgethit.h"
 #include "xfa/fwl/core/ifwl_widgetdelegate.h"
 #include "xfa/fwl/theme/cfwl_widgettp.h"
 
 // FWL contains two parallel inheritance hierarchies, which reference each
 // other via pointers as follows:
 //
 //                  m_pAssociate
@@ skipping 81 matching lines @@
 
   virtual FWL_Error GetMatrix(CFX_Matrix& matrix, FX_BOOL bGlobal = FALSE);
   virtual FWL_Error SetMatrix(const CFX_Matrix& matrix);
 
   virtual FWL_Error DrawWidget(CFX_Graphics* pGraphics,
                                const CFX_Matrix* pMatrix = nullptr);
 
   virtual IFWL_ThemeProvider* GetThemeProvider();
   virtual FWL_Error SetThemeProvider(IFWL_ThemeProvider* pThemeProvider);
 
-  IFWL_WidgetDelegate* GetCurrentDelegate();
-  void SetCurrentDelegate(IFWL_WidgetDelegate* pDelegate);
+  IFWL_WidgetDelegate* GetDelegate() const { return m_pDelegate.get(); }
+  void SetDelegate(std::unique_ptr<IFWL_WidgetDelegate> delegate) {
+    m_pDelegate = std::move(delegate);
+  }
+  std::unique_ptr<IFWL_WidgetDelegate> ReleaseDelegate() {
+    return pdfium::WrapUnique<IFWL_WidgetDelegate>(m_pDelegate.release());
+  }
 
   const IFWL_App* GetOwnerApp() const;
 
   CFX_SizeF GetOffsetFromParent(IFWL_Widget* pParent);
 
   uint32_t GetEventKey() const;
   void SetEventKey(uint32_t key);
 
   void* GetLayoutItem() const;
   void SetLayoutItem(void* pItem);
@@ skipping 67 matching lines @@
                   IFWL_ThemeProvider* pTheme,
                   const CFX_Matrix* pMatrix = nullptr);
   void DrawEdge(CFX_Graphics* pGraphics,
                 CFWL_Part iPartEdge,
                 IFWL_ThemeProvider* pTheme,
                 const CFX_Matrix* pMatrix = nullptr);
   void NotifyDriver();
 
   FX_BOOL IsParent(IFWL_Widget* pParent);
 
-  void SetDelegate(std::unique_ptr<IFWL_WidgetDelegate> delegate) {
-    m_pDelegate = std::move(delegate);
-  }
-  IFWL_WidgetDelegate* GetDelegate() const { return m_pDelegate.get(); }
-
   const IFWL_App* const m_pOwnerApp;
   CFWL_WidgetMgr* const m_pWidgetMgr;
   std::unique_ptr<CFWL_WidgetImpProperties> m_pProperties;
-  IFWL_WidgetDelegate* m_pCurDelegate;  // Not owned.
   IFWL_Widget* m_pOuter;
   void* m_pLayoutItem;
   CFWL_Widget* m_pAssociate;
   int32_t m_iLock;
   uint32_t m_nEventKey;
 
  private:
   std::unique_ptr<IFWL_WidgetDelegate> m_pDelegate;
 };
 
 class CFWL_WidgetImpDelegate : public IFWL_WidgetDelegate {
  public:
   CFWL_WidgetImpDelegate();
   ~CFWL_WidgetImpDelegate() override {}
   void OnProcessMessage(CFWL_Message* pMessage) override;
   void OnProcessEvent(CFWL_Event* pEvent) override;
   void OnDrawWidget(CFX_Graphics* pGraphics,
                     const CFX_Matrix* pMatrix = nullptr) override;
 };
 
 #endif  // XFA_FWL_CORE_IFWL_WIDGET_H_