Invalidate IPWL_FocusHandler and IPWL_Provider on destruction.

fpdfsdk/src/pdfwindow/PWL_Wnd.cpp

 // 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
 
 #include <map>
 
 #include "fpdfsdk/include/pdfwindow/PWL_ScrollBar.h"
 #include "fpdfsdk/include/pdfwindow/PWL_Utils.h"
@@ skipping 219 matching lines @@
     m_bCreated = TRUE;
   }
 }
 
 void CPWL_Wnd::OnCreate(PWL_CREATEPARAM& cp) {}
 
 void CPWL_Wnd::OnCreated() {}
 
 void CPWL_Wnd::OnDestroy() {}
 
+void CPWL_Wnd::InvalidateFocusHandler(IPWL_FocusHandler* handler) {
+  if (m_sPrivateParam.pFocusHandler == handler)
+    m_sPrivateParam.pFocusHandler = nullptr;
+}
+
+void CPWL_Wnd::InvalidateProvider(IPWL_Provider* provider) {
+  if (m_sPrivateParam.pProvider == provider)
+    m_sPrivateParam.pProvider = nullptr;
+}
+
 void CPWL_Wnd::Destroy() {
   KillFocus();
 
   OnDestroy();
 
   if (m_bCreated) {
     for (int32_t i = m_aChildren.GetSize() - 1; i >= 0; i--) {
       if (CPWL_Wnd* pChild = m_aChildren[i]) {
         pChild->Destroy();
         delete pChild;
@@ skipping 804 matching lines @@
   return FALSE;
 }
 
 FX_BOOL CPWL_Wnd::IsINSERTpressed(FX_DWORD nFlag) const {
   if (IFX_SystemHandler* pSystemHandler = GetSystemHandler()) {
     return pSystemHandler->IsINSERTKeyDown(nFlag);
   }
 
   return FALSE;
 }