Remove one (of several) usages of SetPrivateData from IFWL_Widget

xfa/fwl/core/fwl_noteimp.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 "xfa/fwl/core/fwl_noteimp.h"
 
 #include "core/fxcrt/include/fx_ext.h"
+#include "third_party/base/stl_util.h"
 #include "xfa/fwl/basewidget/fwl_tooltipctrlimp.h"
 #include "xfa/fwl/basewidget/ifwl_tooltip.h"
 #include "xfa/fwl/core/cfwl_message.h"
 #include "xfa/fwl/core/cfwl_widgetmgr.h"
 #include "xfa/fwl/core/fwl_appimp.h"
 #include "xfa/fwl/core/fwl_formimp.h"
 #include "xfa/fwl/core/fwl_widgetimp.h"
 #include "xfa/fwl/core/ifwl_app.h"
 #include "xfa/fwl/core/ifwl_tooltiptarget.h"
 
@@ skipping 74 matching lines @@
       CFWL_ToolTipContainer::getInstance()->ProcessLeave(pMouse);
     }
   }
   for (const auto& pair : m_eventTargets) {
     CFWL_EventTarget* pEventTarget = pair.second;
     if (pEventTarget && !pEventTarget->IsInvalid())
       pEventTarget->ProcessEvent(pNote);
   }
 }
 
-#define FWL_NoteDriver_EventKey 1100
 FWL_Error CFWL_NoteDriver::RegisterEventTarget(IFWL_Widget* pListener,
                                                IFWL_Widget* pEventSource,
                                                uint32_t dwFilter) {
-  uint32_t key = (uint32_t)(uintptr_t)pListener->GetPrivateData(
-      (void*)(uintptr_t)FWL_NoteDriver_EventKey);
+  uint32_t key = pListener->GetEventKey();
   if (key == 0) {
-    void* random = FX_Random_MT_Start(0);
-    key = rand();
-    FX_Random_MT_Close(random);
-    pListener->SetPrivateData((void*)(uintptr_t)FWL_NoteDriver_EventKey,
-                              (void*)(uintptr_t)key, NULL);
+    do {
+      key = rand();
+    } while (key == 0 || pdfium::ContainsKey(m_eventTargets, key));
+    pListener->SetEventKey(key);
   }
   if (!m_eventTargets[key])
     m_eventTargets[key] = new CFWL_EventTarget(this, pListener);
 
   m_eventTargets[key]->SetEventSource(pEventSource, dwFilter);
   return FWL_Error::Succeeded;
 }
 
 FWL_Error CFWL_NoteDriver::UnregisterEventTarget(IFWL_Widget* pListener) {
-  uint32_t key = (uint32_t)(uintptr_t)pListener->GetPrivateData(
-      (void*)(uintptr_t)FWL_NoteDriver_EventKey);
+  uint32_t key = pListener->GetEventKey();
   if (key == 0)
     return FWL_Error::Indefinite;
 
   auto it = m_eventTargets.find(key);
   if (it != m_eventTargets.end())
     it->second->FlagInvalid();
 
   return FWL_Error::Succeeded;
 }
 
@@ skipping 751 matching lines @@
   if (HasToolTip(pEvt->m_pDstTarget) && NULL != m_pToolTipImp) {
     m_pToolTipImp->Hide();
     pCurTarget = NULL;
     return TRUE;
   }
   return FALSE;
 }
 IFWL_ToolTipTarget* CFWL_ToolTipContainer::GetCurrentToolTipTarget() {
   return pCurTarget;
 }