Add CFDE_TxtEdtBuf tests

xfa/fde/cfde_txtedtbuf.h

Index: xfa/fde/cfde_txtedtbuf.h
diff --git a/xfa/fde/cfde_txtedtbuf.h b/xfa/fde/cfde_txtedtbuf.h
index ac25a080e5c7a7e5e1c37e69c04f8f9b1e255d28..63edbf6167f5d908274f90003c02487e43e51c01 100644
--- a/xfa/fde/cfde_txtedtbuf.h
+++ b/xfa/fde/cfde_txtedtbuf.h
@@ -25,16 +25,15 @@ class CFDE_TxtEdtBuf {
   void SetText(const CFX_WideString& wsText);
   CFX_WideString GetText() const;
   FX_WCHAR GetCharByIndex(int32_t nIndex) const;
-  CFX_WideString GetRange(int32_t nBegin, int32_t nCount = -1) const;
+  CFX_WideString GetRange(int32_t nBegin, int32_t nCount) const;
 
-  void Insert(int32_t nPos, const FX_WCHAR* lpText, int32_t nLength = 1);
-  void Delete(int32_t nIndex, int32_t nLength = 1);
-  void Clear(bool bRelease = true);
-
-  bool Optimize(IFX_Pause* pPause = nullptr);
+  void Insert(int32_t nPos, const FX_WCHAR* lpText, int32_t nLength);
+  void Delete(int32_t nIndex, int32_t nLength);
+  void Clear(bool bRelease);
 
  private:
   friend class CFDE_TxtEdtBufIter;
+  friend class CFDE_TxtEdtBufTest;
 
   struct FDE_CHUNKHEADER {
     int32_t nUsed;
@@ -50,6 +49,8 @@ class CFDE_TxtEdtBuf {
   int32_t CP2Index(const FDE_CHUNKPLACE& cp) const;
   void Index2CP(int32_t nIndex, FDE_CHUNKPLACE& cp) const;
 
+  void SetChunkSizeForTesting(size_t size);
+
   int32_t m_nChunkSize;
 
   int32_t m_nTotal;