Fold the FWL NoteThread classes up to the Thread classes.

xfa/fwl/core/ifwl_thread.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_THREAD_H_
 #define XFA_FWL_CORE_IFWL_THREAD_H_
 
 // The FWL thread/app code contains three parallel inheritance hierarchies,
 // which reference each other via pointers as follows:
 //
 //                                           m_pImpl
 //      (nonesuch)              IFWL_Thread ----------> CFWL_ThreadImp
 //                                   |      <----------      |
 //                                   A       m_pIface        A
-//                                   |                       |
-//      (nonesuch)              IFWL_NoteThread         CFWL_NoteThreadImp
-//                                   |                       |
-//                                   A                       A
 //                m_pIface           |                       |
-//      CFWL_App --------------> IFWL_App                CFWL_AppImp
+//      CXFA_FFApp ------------> IFWL_App                CFWL_AppImp
 //
 
 #include "xfa/fwl/core/fwl_error.h"
 
 class CFWL_ThreadImp;
 class IFWL_NoteDriver;
 
 class IFWL_Thread {
  public:
   // These call into polymorphic methods in the impl; no need to override.
   void Release();
 
   CFWL_ThreadImp* GetImpl() const { return m_pImpl; }
   void SetImpl(CFWL_ThreadImp* pImpl) { m_pImpl = pImpl; }
 
+  IFWL_NoteDriver* GetNoteDriver() const;
+
  protected:
   virtual ~IFWL_Thread() {}
 
  private:
   CFWL_ThreadImp* m_pImpl;
 };
 
 #endif  // XFA_FWL_CORE_IFWL_THREAD_H_