More FWL interface cleanup.

xfa/fwl/core/ifwl_app.h

Index: xfa/fwl/core/ifwl_app.h
diff --git a/xfa/fwl/core/ifwl_app.h b/xfa/fwl/core/ifwl_app.h
index 3fb0940ed42cab6c635b3cd2890ced12b46ba9f6..53dc35d33ab9f386d0a358506579416874445af0 100644
--- a/xfa/fwl/core/ifwl_app.h
+++ b/xfa/fwl/core/ifwl_app.h
@@ -7,19 +7,33 @@
 #ifndef XFA_FWL_CORE_IFWL_APP_H_
 #define XFA_FWL_CORE_IFWL_APP_H_
 
+// The FWL thread/app code contains three parallel classes, which reference each
+// other via pointers as follows:
+//
+//                    m_pIface               m_pImpl
+//      CXFA_FFApp ------------> IFWL_App -----------> CFWL_AppImp
+//                                        <-----------
+//                                           m_pIface
+
+#include <memory>
+
 #include "core/fxcrt/include/fx_string.h"
-#include "xfa/fwl/core/ifwl_thread.h"
+#include "xfa/fwl/core/fwl_appimp.h"
+#include "xfa/fwl/core/fwl_error.h"
 
+class CFWL_NoteDriver;
 class IFWL_AdapterNative;
+class IFWL_AdapterWidgetMgr;
+class IFWL_ThemeProvider;
 class IFWL_Widget;
 class IFWL_WidgetMgr;
-class IFWL_ThemeProvider;
-class IFWL_AdapterWidgetMgr;
 
-class IFWL_App : public IFWL_Thread {
+class IFWL_App {
  public:
   static IFWL_App* Create(IFWL_AdapterNative* pAdapter);
 
+  virtual ~IFWL_App() {}
+
   FWL_ERR Initialize();
   FWL_ERR Finalize();
   IFWL_AdapterNative* GetAdapterNative();
@@ -28,8 +42,20 @@ class IFWL_App : public IFWL_Thread {
   FWL_ERR SetThemeProvider(IFWL_ThemeProvider* pThemeProvider);
   FWL_ERR Exit(int32_t iExitCode);
 
+  // These call into polymorphic methods in the impl; no need to override.
+  void Release();
+
+  CFWL_AppImp* GetImpl() const { return m_pImpl.get(); }
+
+  // Takes ownership of |pImpl|.
+  void SetImpl(CFWL_AppImp* pImpl) { m_pImpl.reset(pImpl); }
+
+  CFWL_NoteDriver* GetNoteDriver() const;
+
  private:
   IFWL_App() {}
+
+  std::unique_ptr<CFWL_AppImp> m_pImpl;
 };
 
 IFWL_App* FWL_GetApp();