Make code compile with clang_use_chrome_plugin (part VI)

This change mainly contains files in xfa/fwl directory.
This is part of the efforts to make PDFium code compilable
by Clang chromium style plugins.

The changes are mainly the following:
-- move inline constructor/destructor of complex class/struct out-of-line;
-- add constructor/destructor of complex class/struct if not
 explicitly defined;
-- add explicit out-of-line copy constructor when needed;
-- move inline virtual functions out-of-line;
-- Properly mark virtual functions with 'override';
-- some minor cleanups;

BUG=pdfium:469

Review-Url: https://codereview.chromium.org/2070583003

1 files changed, 2 insertions, 2 deletions

diff --git a/xfa/fwl/core/ifwl_app.h b/xfa/fwl/core/ifwl_app.h
index 5fbac6644f..27c65c8317 100644
--- a/xfa/fwl/core/ifwl_app.h
+++ b/xfa/fwl/core/ifwl_app.h
@@ -32,7 +32,7 @@ class IFWL_App {
  public:
   static IFWL_App* Create(CXFA_FFApp* pAdapter);
 
-  virtual ~IFWL_App() {}
+  virtual ~IFWL_App();
 
   FWL_Error Initialize();
   FWL_Error Finalize();
@@ -53,7 +53,7 @@ class IFWL_App {
   CFWL_NoteDriver* GetNoteDriver() const;
 
  private:
-  IFWL_App() {}
+  IFWL_App();
 
   std::unique_ptr<CFWL_AppImp> m_pImpl;
 };