Cleanup remaining IFWL files for visiblity and usage.

This CL cleans up the remaining ifwl_* files to fixup visibility, remove
unused methods and remove unused FWL_Error return codes.

Review-Url: https://codereview.chromium.org/2502653002
diff --git a/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.cpp b/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.cpp
index f5e36d4..5a9ae95 100644
--- a/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.cpp
+++ b/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.cpp
@@ -13,12 +13,12 @@
 
 std::vector<CFWL_TimerInfo*>* CXFA_FWLAdapterTimerMgr::s_TimerArray = nullptr;
 
-FWL_Error CXFA_FWLAdapterTimerMgr::Start(IFWL_Timer* pTimer,
-                                         uint32_t dwElapse,
-                                         bool bImmediately,
-                                         IFWL_TimerInfo** pTimerInfo) {
+void CXFA_FWLAdapterTimerMgr::Start(IFWL_Timer* pTimer,
+                                    uint32_t dwElapse,
+                                    bool bImmediately,
+                                    IFWL_TimerInfo** pTimerInfo) {
   if (!m_pFormFillEnv)
-    return FWL_Error::Indefinite;
+    return;
 
   int32_t id_event = m_pFormFillEnv->SetTimer(dwElapse, TimerProc);
   if (!s_TimerArray)
@@ -26,12 +26,11 @@
 
   s_TimerArray->push_back(new CFWL_TimerInfo(this, id_event, pTimer));
   *pTimerInfo = s_TimerArray->back();
-  return FWL_Error::Succeeded;
 }
 
-FWL_Error CXFA_FWLAdapterTimerMgr::Stop(IFWL_TimerInfo* pTimerInfo) {
+void CXFA_FWLAdapterTimerMgr::Stop(IFWL_TimerInfo* pTimerInfo) {
   if (!pTimerInfo || !m_pFormFillEnv)
-    return FWL_Error::Indefinite;
+    return;
 
   CFWL_TimerInfo* pInfo = static_cast<CFWL_TimerInfo*>(pTimerInfo);
   m_pFormFillEnv->KillTimer(pInfo->idEvent);
@@ -42,7 +41,6 @@
       delete pInfo;
     }
   }
-  return FWL_Error::Succeeded;
 }
 
 // static
diff --git a/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.h b/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.h
index ee4b404..2a1c509 100644
--- a/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.h
+++ b/fpdfsdk/fpdfxfa/cxfa_fwladaptertimermgr.h
@@ -19,11 +19,11 @@
   CXFA_FWLAdapterTimerMgr(CPDFSDK_FormFillEnvironment* pFormFillEnv)
       : m_pFormFillEnv(pFormFillEnv) {}
 
-  FWL_Error Start(IFWL_Timer* pTimer,
-                  uint32_t dwElapse,
-                  bool bImmediately,
-                  IFWL_TimerInfo** pTimerInfo) override;
-  FWL_Error Stop(IFWL_TimerInfo* pTimerInfo) override;
+  void Start(IFWL_Timer* pTimer,
+             uint32_t dwElapse,
+             bool bImmediately,
+             IFWL_TimerInfo** pTimerInfo) override;
+  void Stop(IFWL_TimerInfo* pTimerInfo) override;
 
  protected:
   static void TimerProc(int32_t idEvent);
diff --git a/xfa/fwl/core/cfwl_barcode.cpp b/xfa/fwl/core/cfwl_barcode.cpp
index 053826d..ef3ae40 100644
--- a/xfa/fwl/core/cfwl_barcode.cpp
+++ b/xfa/fwl/core/cfwl_barcode.cpp
@@ -83,11 +83,6 @@
   m_cEndChar = endChar;
 }
 
-void CFWL_Barcode::SetVersion(int32_t version) {
-  m_dwAttributeMask |= FWL_BCDATTRIBUTE_VERSION;
-  m_nVersion = version;
-}
-
 void CFWL_Barcode::SetErrorCorrectionLevel(int32_t ecLevel) {
   m_dwAttributeMask |= FWL_BCDATTRIBUTE_ECLEVEL;
   m_nECLevel = ecLevel;
@@ -98,10 +93,6 @@
   m_bTruncated = truncated;
 }
 
-void CFWL_Barcode::ResetBarcodeAttributes() {
-  m_dwAttributeMask = FWL_BCDATTRIBUTE_NONE;
-}
-
 void CFWL_Barcode::SetType(BC_TYPE type) {
   if (GetWidget())
     ToBarcode(GetWidget())->SetType(type);
@@ -155,7 +146,7 @@
 }
 
 int32_t CFWL_Barcode::GetVersion() const {
-  return m_nVersion;
+  return 0;
 }
 
 int32_t CFWL_Barcode::GetErrorCorrectionLevel() const {
diff --git a/xfa/fwl/core/cfwl_barcode.h b/xfa/fwl/core/cfwl_barcode.h
index 78e5e68..30d158c 100644
--- a/xfa/fwl/core/cfwl_barcode.h
+++ b/xfa/fwl/core/cfwl_barcode.h
@@ -18,24 +18,6 @@
 
   void Initialize();
 
-  void SetType(BC_TYPE type);
-  bool IsProtectedType();
-
-  void SetCharEncoding(BC_CHAR_ENCODING encoding);
-  void SetModuleHeight(int32_t height);
-  void SetModuleWidth(int32_t width);
-  void SetDataLength(int32_t dataLength);
-  void SetCalChecksum(bool calChecksum);
-  void SetPrintChecksum(bool printChecksum);
-  void SetTextLocation(BC_TEXT_LOC location);
-  void SetWideNarrowRatio(int32_t ratio);
-  void SetStartChar(FX_CHAR startChar);
-  void SetEndChar(FX_CHAR endChar);
-  void SetVersion(int32_t version);
-  void SetErrorCorrectionLevel(int32_t ecLevel);
-  void SetTruncated(bool truncated);
-  void ResetBarcodeAttributes();
-
   // IFWL_DataProvider
   void GetCaption(IFWL_Widget* pWidget, CFX_WideString& wsCaption) override;
 
@@ -55,6 +37,22 @@
   bool GetTruncated() const override;
   uint32_t GetBarcodeAttributeMask() const override;
 
+  void SetType(BC_TYPE type);
+  bool IsProtectedType();
+
+  void SetCharEncoding(BC_CHAR_ENCODING encoding);
+  void SetModuleHeight(int32_t height);
+  void SetModuleWidth(int32_t width);
+  void SetDataLength(int32_t dataLength);
+  void SetCalChecksum(bool calChecksum);
+  void SetPrintChecksum(bool printChecksum);
+  void SetTextLocation(BC_TEXT_LOC location);
+  void SetWideNarrowRatio(int32_t ratio);
+  void SetStartChar(FX_CHAR startChar);
+  void SetEndChar(FX_CHAR endChar);
+  void SetErrorCorrectionLevel(int32_t ecLevel);
+  void SetTruncated(bool truncated);
+
  private:
   BC_CHAR_ENCODING m_eCharEncoding;
   int32_t m_nModuleHeight;
@@ -66,7 +64,6 @@
   int32_t m_nWideNarrowRatio;
   FX_CHAR m_cStartChar;
   FX_CHAR m_cEndChar;
-  int32_t m_nVersion;
   int32_t m_nECLevel;
   bool m_bTruncated;
   uint32_t m_dwAttributeMask;
diff --git a/xfa/fwl/core/cfwl_checkbox.cpp b/xfa/fwl/core/cfwl_checkbox.cpp
index 75e85fc..08371fc 100644
--- a/xfa/fwl/core/cfwl_checkbox.cpp
+++ b/xfa/fwl/core/cfwl_checkbox.cpp
@@ -11,14 +11,6 @@
 #include "third_party/base/ptr_util.h"
 #include "xfa/fwl/core/fwl_error.h"
 
-namespace {
-
-IFWL_CheckBox* ToCheckBox(IFWL_Widget* widget) {
-  return static_cast<IFWL_CheckBox*>(widget);
-}
-
-}  // namespace
-
 CFWL_CheckBox::CFWL_CheckBox(const IFWL_App* app)
     : CFWL_Widget(app), m_fBoxHeight(16.0f), m_wsCaption(L"Check box") {}
 
@@ -33,22 +25,8 @@
   CFWL_Widget::Initialize();
 }
 
-FWL_Error CFWL_CheckBox::SetCaption(const CFX_WideStringC& wsCaption) {
-  m_wsCaption = wsCaption;
-  return FWL_Error::Succeeded;
-}
-
-FWL_Error CFWL_CheckBox::SetBoxSize(FX_FLOAT fHeight) {
+void CFWL_CheckBox::SetBoxSize(FX_FLOAT fHeight) {
   m_fBoxHeight = fHeight;
-  return FWL_Error::Succeeded;
-}
-
-int32_t CFWL_CheckBox::GetCheckState() {
-  return ToCheckBox(GetWidget())->GetCheckState();
-}
-
-FWL_Error CFWL_CheckBox::SetCheckState(int32_t iCheck) {
-  return ToCheckBox(GetWidget())->SetCheckState(iCheck);
 }
 
 void CFWL_CheckBox::GetCaption(IFWL_Widget* pWidget,
diff --git a/xfa/fwl/core/cfwl_checkbox.h b/xfa/fwl/core/cfwl_checkbox.h
index 730b906..fb7a9ae 100644
--- a/xfa/fwl/core/cfwl_checkbox.h
+++ b/xfa/fwl/core/cfwl_checkbox.h
@@ -17,17 +17,14 @@
 
   void Initialize();
 
-  FWL_Error SetCaption(const CFX_WideStringC& wsCaption);
-  FWL_Error SetBoxSize(FX_FLOAT fHeight);
-  int32_t GetCheckState();
-  FWL_Error SetCheckState(int32_t iCheck);
-
   // IFWL_DataProvider
   void GetCaption(IFWL_Widget* pWidget, CFX_WideString& wsCaption) override;
 
   // IFWL_CheckBoxDP
   FX_FLOAT GetBoxSize(IFWL_Widget* pWidget) override;
 
+  void SetBoxSize(FX_FLOAT fHeight);
+
  private:
   FX_FLOAT m_fBoxHeight;
   CFX_WideString m_wsCaption;
diff --git a/xfa/fwl/core/cfwl_picturebox.cpp b/xfa/fwl/core/cfwl_picturebox.cpp
index 8badc99..b701ae7 100644
--- a/xfa/fwl/core/cfwl_picturebox.cpp
+++ b/xfa/fwl/core/cfwl_picturebox.cpp
@@ -114,7 +114,7 @@
   return m_iOpacity;
 }
 
-FWL_Error CFWL_PictureBox::GetMatrix(IFWL_Widget* pWidget, CFX_Matrix& matrix) {
+void CFWL_PictureBox::GetMatrix(IFWL_Widget* pWidget, CFX_Matrix& matrix) {
   CFX_RectF rect;
   pWidget->GetClientRect(rect);
   FX_FLOAT fLen = rect.width / 2;
@@ -125,7 +125,6 @@
   matrix.Translate(fLen, fWid);
   matrix.Scale(m_fScaleX, m_fScaleY);
   matrix.Translate(m_fOffSetX, m_fOffSetY);
-  return FWL_Error::Succeeded;
 }
 
 int32_t CFWL_PictureBox::GetFlipMode(IFWL_Widget* pWidget) {
diff --git a/xfa/fwl/core/cfwl_picturebox.h b/xfa/fwl/core/cfwl_picturebox.h
index 1efa0ad..8613721 100644
--- a/xfa/fwl/core/cfwl_picturebox.h
+++ b/xfa/fwl/core/cfwl_picturebox.h
@@ -18,6 +18,17 @@
 
   void Initialize();
 
+  // IFWL_DataProvider
+  void GetCaption(IFWL_Widget* pWidget, CFX_WideString& wsCaption) override;
+
+  // IFWL_PictureBoxDP
+  CFX_DIBitmap* GetPicture(IFWL_Widget* pWidget) override;
+  CFX_DIBitmap* GetErrorPicture(IFWL_Widget* pWidget) override;
+  CFX_DIBitmap* GetInitialPicture(IFWL_Widget* pWidget) override;
+  int32_t GetOpacity(IFWL_Widget* pWidget) override;
+  int32_t GetFlipMode(IFWL_Widget* pWidget) override;
+  void GetMatrix(IFWL_Widget* pWidget, CFX_Matrix& matrix) override;
+
   CFX_DIBitmap* GetPicture();
   FWL_Error SetPicture(CFX_DIBitmap* pBitmap);
   FX_FLOAT GetRotation();
@@ -31,16 +42,6 @@
   FWL_Error GetOffset(FX_FLOAT& fx, FX_FLOAT& fy);
   FWL_Error SetOffset(FX_FLOAT fx, FX_FLOAT fy);
 
-  // IFWL_DataProvider
-  void GetCaption(IFWL_Widget* pWidget, CFX_WideString& wsCaption) override;
-
-  // IFWL_PictureBoxDP
-  CFX_DIBitmap* GetPicture(IFWL_Widget* pWidget) override;
-  CFX_DIBitmap* GetErrorPicture(IFWL_Widget* pWidget) override;
-  CFX_DIBitmap* GetInitialPicture(IFWL_Widget* pWidget) override;
-  int32_t GetOpacity(IFWL_Widget* pWidget) override;
-  int32_t GetFlipMode(IFWL_Widget* pWidget) override;
-  FWL_Error GetMatrix(IFWL_Widget* pWidget, CFX_Matrix& matrix) override;
 
  private:
   CFX_DIBitmap* m_pBitmap;
diff --git a/xfa/fwl/core/ifwl_adaptertimermgr.h b/xfa/fwl/core/ifwl_adaptertimermgr.h
index ef5ebba..156c0cf 100644
--- a/xfa/fwl/core/ifwl_adaptertimermgr.h
+++ b/xfa/fwl/core/ifwl_adaptertimermgr.h
@@ -7,17 +7,16 @@
 #ifndef XFA_FWL_CORE_IFWL_ADAPTERTIMERMGR_H_
 #define XFA_FWL_CORE_IFWL_ADAPTERTIMERMGR_H_
 
-#include "xfa/fwl/core/fwl_error.h"
 #include "xfa/fwl/core/ifwl_timer.h"
 
 class IFWL_AdapterTimerMgr {
  public:
   virtual ~IFWL_AdapterTimerMgr() {}
-  virtual FWL_Error Start(IFWL_Timer* pTimer,
-                          uint32_t dwElapse,
-                          bool bImmediately,
-                          IFWL_TimerInfo** pTimerInfo) = 0;
-  virtual FWL_Error Stop(IFWL_TimerInfo* pTimerInfo) = 0;
+  virtual void Start(IFWL_Timer* pTimer,
+                     uint32_t dwElapse,
+                     bool bImmediately,
+                     IFWL_TimerInfo** pTimerInfo) = 0;
+  virtual void Stop(IFWL_TimerInfo* pTimerInfo) = 0;
 };
 
 #endif  // XFA_FWL_CORE_IFWL_ADAPTERTIMERMGR_H_
diff --git a/xfa/fwl/core/ifwl_barcode.h b/xfa/fwl/core/ifwl_barcode.h
index 1d88c32..d69cd23 100644
--- a/xfa/fwl/core/ifwl_barcode.h
+++ b/xfa/fwl/core/ifwl_barcode.h
@@ -58,8 +58,8 @@
 
 class IFWL_Barcode : public IFWL_Edit {
  public:
-  explicit IFWL_Barcode(const IFWL_App* app,
-                        std::unique_ptr<CFWL_WidgetProperties> properties);
+  IFWL_Barcode(const IFWL_App* app,
+               std::unique_ptr<CFWL_WidgetProperties> properties);
   ~IFWL_Barcode() override;
 
   // IFWL_Widget
@@ -75,7 +75,7 @@
   void SetType(BC_TYPE type);
   bool IsProtectedType();
 
- protected:
+ private:
   void GenerateBarcodeImageCache();
   void CreateBarcodeEngine();
 
diff --git a/xfa/fwl/core/ifwl_caret.cpp b/xfa/fwl/core/ifwl_caret.cpp
index 78ac4e5..f333fdd 100644
--- a/xfa/fwl/core/ifwl_caret.cpp
+++ b/xfa/fwl/core/ifwl_caret.cpp
@@ -13,14 +13,18 @@
 #include "xfa/fwl/core/ifwl_caret.h"
 #include "xfa/fwl/core/ifwl_themeprovider.h"
 
+namespace {
+
+const uint32_t kFrequency = 400;
+
+}  // namespace
+
 IFWL_Caret::IFWL_Caret(const IFWL_App* app,
                        std::unique_ptr<CFWL_WidgetProperties> properties,
                        IFWL_Widget* pOuter)
     : IFWL_Widget(app, std::move(properties), pOuter),
       m_pTimer(new IFWL_Caret::Timer(this)),
-      m_pTimerInfo(nullptr),
-      m_dwElapse(400),
-      m_bSetColor(false) {
+      m_pTimerInfo(nullptr) {
   SetStates(FWL_STATE_CAT_HightLight);
 }
 
@@ -53,27 +57,11 @@
     m_pTimerInfo = nullptr;
   }
   if (bFlag)
-    m_pTimerInfo = m_pTimer->StartTimer(m_dwElapse, true);
+    m_pTimerInfo = m_pTimer->StartTimer(kFrequency, true);
 
   SetStates(FWL_WGTSTATE_Invisible, !bFlag);
 }
 
-FWL_Error IFWL_Caret::GetFrequency(uint32_t& elapse) {
-  elapse = m_dwElapse;
-  return FWL_Error::Succeeded;
-}
-
-FWL_Error IFWL_Caret::SetFrequency(uint32_t elapse) {
-  m_dwElapse = elapse;
-  return FWL_Error::Succeeded;
-}
-
-FWL_Error IFWL_Caret::SetColor(CFX_Color crFill) {
-  m_bSetColor = true;
-  m_crFill = crFill;
-  return FWL_Error::Succeeded;
-}
-
 void IFWL_Caret::DrawCaretBK(CFX_Graphics* pGraphics,
                              IFWL_ThemeProvider* pTheme,
                              const CFX_Matrix* pMatrix) {
@@ -84,8 +72,6 @@
   param.m_pWidget = this;
   param.m_pGraphics = pGraphics;
   param.m_rtPart = rect;
-  if (m_bSetColor)
-    param.m_pData = &m_crFill;
   if (!(m_pProperties->m_dwStates & FWL_STATE_CAT_HightLight))
     return;
 
diff --git a/xfa/fwl/core/ifwl_caret.h b/xfa/fwl/core/ifwl_caret.h
index dc1d580..d75a662 100644
--- a/xfa/fwl/core/ifwl_caret.h
+++ b/xfa/fwl/core/ifwl_caret.h
@@ -34,11 +34,8 @@
                     const CFX_Matrix* pMatrix) override;
 
   void ShowCaret(bool bFlag = true);
-  FWL_Error GetFrequency(uint32_t& elapse);
-  FWL_Error SetFrequency(uint32_t elapse);
-  FWL_Error SetColor(CFX_Color crFill);
 
- protected:
+ private:
   class Timer : public IFWL_Timer {
    public:
     explicit Timer(IFWL_Caret* pCaret);
@@ -54,9 +51,6 @@
 
   std::unique_ptr<IFWL_Caret::Timer> m_pTimer;
   IFWL_TimerInfo* m_pTimerInfo;  // not owned.
-  uint32_t m_dwElapse;
-  CFX_Color m_crFill;
-  bool m_bSetColor;
 };
 
 #endif  // XFA_FWL_CORE_IFWL_CARET_H_
diff --git a/xfa/fwl/core/ifwl_checkbox.cpp b/xfa/fwl/core/ifwl_checkbox.cpp
index 3aac359..76a377a 100644
--- a/xfa/fwl/core/ifwl_checkbox.cpp
+++ b/xfa/fwl/core/ifwl_checkbox.cpp
@@ -143,39 +143,20 @@
   }
 }
 
-int32_t IFWL_CheckBox::GetCheckState() {
-  if ((m_pProperties->m_dwStyleExes & FWL_STYLEEXT_CKB_3State) &&
-      ((m_pProperties->m_dwStates & FWL_STATE_CKB_CheckMask) ==
-       FWL_STATE_CKB_Neutral)) {
-    return 2;
-  }
-  if ((m_pProperties->m_dwStates & FWL_STATE_CKB_CheckMask) ==
-      FWL_STATE_CKB_Checked) {
-    return 1;
-  }
-  return 0;
-}
-
-FWL_Error IFWL_CheckBox::SetCheckState(int32_t iCheck) {
+void IFWL_CheckBox::SetCheckState(int32_t iCheck) {
   m_pProperties->m_dwStates &= ~FWL_STATE_CKB_CheckMask;
   switch (iCheck) {
-    case 0: {
-      break;
-    }
-    case 1: {
+    case 1:
       m_pProperties->m_dwStates |= FWL_STATE_CKB_Checked;
       break;
-    }
-    case 2: {
-      if (m_pProperties->m_dwStyleExes & FWL_STYLEEXT_CKB_3State) {
+    case 2:
+      if (m_pProperties->m_dwStyleExes & FWL_STYLEEXT_CKB_3State)
         m_pProperties->m_dwStates |= FWL_STATE_CKB_Neutral;
-      }
       break;
-    }
-    default: {}
+    default:
+      break;
   }
   Repaint(&m_rtClient);
-  return FWL_Error::Succeeded;
 }
 
 void IFWL_CheckBox::Layout() {
diff --git a/xfa/fwl/core/ifwl_checkbox.h b/xfa/fwl/core/ifwl_checkbox.h
index d3dfd26..cda02b5 100644
--- a/xfa/fwl/core/ifwl_checkbox.h
+++ b/xfa/fwl/core/ifwl_checkbox.h
@@ -56,8 +56,8 @@
 
 class IFWL_CheckBox : public IFWL_Widget {
  public:
-  explicit IFWL_CheckBox(const IFWL_App* app,
-                         std::unique_ptr<CFWL_WidgetProperties> properties);
+  IFWL_CheckBox(const IFWL_App* app,
+                std::unique_ptr<CFWL_WidgetProperties> properties);
   ~IFWL_CheckBox() override;
 
   // IFWL_Widget
@@ -71,14 +71,19 @@
   void OnDrawWidget(CFX_Graphics* pGraphics,
                     const CFX_Matrix* pMatrix) override;
 
-  int32_t GetCheckState();
-  FWL_Error SetCheckState(int32_t iCheck);
-
- protected:
+ private:
+  void SetCheckState(int32_t iCheck);
   void Layout();
   uint32_t GetPartStates();
   void UpdateTextOutStyles();
   void NextStates();
+  void OnActivate(CFWL_Message* pMsg);
+  void OnFocusChanged(CFWL_Message* pMsg, bool bSet);
+  void OnLButtonDown(CFWL_MsgMouse* pMsg);
+  void OnLButtonUp(CFWL_MsgMouse* pMsg);
+  void OnMouseMove(CFWL_MsgMouse* pMsg);
+  void OnMouseLeave(CFWL_MsgMouse* pMsg);
+  void OnKeyDown(CFWL_MsgKey* pMsg);
 
   CFX_RectF m_rtClient;
   CFX_RectF m_rtBox;
@@ -87,15 +92,6 @@
   uint32_t m_dwTTOStyles;
   int32_t m_iTTOAlign;
   bool m_bBtnDown;
-
- private:
-  void OnActivate(CFWL_Message* pMsg);
-  void OnFocusChanged(CFWL_Message* pMsg, bool bSet);
-  void OnLButtonDown(CFWL_MsgMouse* pMsg);
-  void OnLButtonUp(CFWL_MsgMouse* pMsg);
-  void OnMouseMove(CFWL_MsgMouse* pMsg);
-  void OnMouseLeave(CFWL_MsgMouse* pMsg);
-  void OnKeyDown(CFWL_MsgKey* pMsg);
 };
 
 #endif  // XFA_FWL_CORE_IFWL_CHECKBOX_H_
diff --git a/xfa/fwl/core/ifwl_picturebox.h b/xfa/fwl/core/ifwl_picturebox.h
index 55eabcb..41b09f4 100644
--- a/xfa/fwl/core/ifwl_picturebox.h
+++ b/xfa/fwl/core/ifwl_picturebox.h
@@ -36,7 +36,7 @@
   virtual CFX_DIBitmap* GetInitialPicture(IFWL_Widget* pWidget) = 0;
   virtual int32_t GetOpacity(IFWL_Widget* pWidget) = 0;
   virtual int32_t GetFlipMode(IFWL_Widget* pWidget) = 0;
-  virtual FWL_Error GetMatrix(IFWL_Widget* pWidget, CFX_Matrix& matrix) = 0;
+  virtual void GetMatrix(IFWL_Widget* pWidget, CFX_Matrix& matrix) = 0;
 };
 
 class IFWL_PictureBox : public IFWL_Widget {