Change IFWL_Widget to store a single delegate.

xfa/fxfa/app/xfa_ffimageedit.cpp

Index: xfa/fxfa/app/xfa_ffimageedit.cpp
diff --git a/xfa/fxfa/app/xfa_ffimageedit.cpp b/xfa/fxfa/app/xfa_ffimageedit.cpp
index 9e29119671039c419caf4ef193fc6cb46f2ad851..c174c6f673300e3396a4e72064218d67ae7a2b45 100644
--- a/xfa/fxfa/app/xfa_ffimageedit.cpp
+++ b/xfa/fxfa/app/xfa_ffimageedit.cpp
@@ -6,10 +6,12 @@
 
 #include "xfa/fxfa/app/xfa_ffimageedit.h"
 
+#include "third_party/base/ptr_util.h"
 #include "xfa/fwl/core/cfwl_message.h"
 #include "xfa/fwl/core/cfwl_picturebox.h"
 #include "xfa/fwl/core/fwl_noteimp.h"
 #include "xfa/fwl/core/ifwl_app.h"
+#include "xfa/fxfa/app/cxfa_ffimageeditdelegate.h"
 #include "xfa/fxfa/app/xfa_fffield.h"
 #include "xfa/fxfa/xfa_ffdoc.h"
 #include "xfa/fxfa/xfa_ffdocview.h"
@@ -18,7 +20,8 @@
 
 CXFA_FFImageEdit::CXFA_FFImageEdit(CXFA_FFPageView* pPageView,
                                    CXFA_WidgetAcc* pDataAcc)
-    : CXFA_FFField(pPageView, pDataAcc), m_pOldDelegate(nullptr) {}
+    : CXFA_FFField(pPageView, pDataAcc) {}
+
 CXFA_FFImageEdit::~CXFA_FFImageEdit() {
   CXFA_FFImageEdit::UnloadWidget();
 }
@@ -32,8 +35,8 @@ FX_BOOL CXFA_FFImageEdit::LoadWidget() {
   CFWL_NoteDriver* pNoteDriver = pWidget->GetOwnerApp()->GetNoteDriver();
   pNoteDriver->RegisterEventTarget(pWidget, pWidget);
 
-  m_pOldDelegate = pPictureBox->GetCurrentDelegate();
-  pPictureBox->SetCurrentDelegate(this);
+  pPictureBox->SetDelegate(pdfium::MakeUnique<CXFA_FFImageEditDelegate>(
+      pPictureBox->ReleaseDelegate(), this));
 
   CXFA_FFField::LoadWidget();
   if (m_pDataAcc->GetImageEditImage()) {
@@ -125,16 +128,3 @@ FX_BOOL CXFA_FFImageEdit::UpdateFWLData() {
   return TRUE;
 }
 
-void CXFA_FFImageEdit::OnProcessMessage(CFWL_Message* pMessage) {
-  m_pOldDelegate->OnProcessMessage(pMessage);
-}
-
-void CXFA_FFImageEdit::OnProcessEvent(CFWL_Event* pEvent) {
-  CXFA_FFField::OnProcessEvent(pEvent);
-  m_pOldDelegate->OnProcessEvent(pEvent);
-}
-
-void CXFA_FFImageEdit::OnDrawWidget(CFX_Graphics* pGraphics,
-                                    const CFX_Matrix* pMatrix) {
-  m_pOldDelegate->OnDrawWidget(pGraphics, pMatrix);
-}