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, 12 insertions, 6 deletions

diff --git a/xfa/fwl/lightwidget/cfwl_checkbox.h b/xfa/fwl/lightwidget/cfwl_checkbox.h
index 061e46f777..7fcd43a6eb 100644
--- a/xfa/fwl/lightwidget/cfwl_checkbox.h
+++ b/xfa/fwl/lightwidget/cfwl_checkbox.h
@@ -12,27 +12,33 @@
 
 class CFWL_CheckBox : public CFWL_Widget {
  public:
+  CFWL_CheckBox();
+  ~CFWL_CheckBox() override;
+
   static CFWL_CheckBox* Create();
 
   FWL_Error Initialize(const CFWL_WidgetProperties* pProperties = NULL);
-  FWL_Error GetCaption(CFX_WideString& wsCaption);
   FWL_Error SetCaption(const CFX_WideStringC& wsCaption);
   FWL_Error SetBoxSize(FX_FLOAT fHeight);
   int32_t GetCheckState();
   FWL_Error SetCheckState(int32_t iCheck);
-  CFWL_CheckBox();
-  virtual ~CFWL_CheckBox();
 
  protected:
   class CFWL_CheckBoxDP : public IFWL_CheckBoxDP {
    public:
     CFWL_CheckBoxDP();
-    virtual FWL_Error GetCaption(IFWL_Widget* pWidget,
-                                 CFX_WideString& wsCaption);
-    virtual FX_FLOAT GetBoxSize(IFWL_Widget* pWidget);
+
+    // IFWL_DataProvider
+    FWL_Error GetCaption(IFWL_Widget* pWidget,
+                         CFX_WideString& wsCaption) override;
+
+    // IFWL_CheckBoxDP
+    FX_FLOAT GetBoxSize(IFWL_Widget* pWidget) override;
+
     FX_FLOAT m_fBoxHeight;
     CFX_WideString m_wsCaption;
   };
+
   CFWL_CheckBoxDP m_checkboxData;
 };