diff --git a/core/fpdfapi/font/cpdf_font.cpp b/core/fpdfapi/font/cpdf_font.cpp
index 5647627..a714894 100644
--- a/core/fpdfapi/font/cpdf_font.cpp
+++ b/core/fpdfapi/font/cpdf_font.cpp
@@ -131,7 +131,7 @@
 void CPDF_Font::AppendChar(ByteString* str, uint32_t charcode) const {
   char buf[4];
   int len = AppendChar(buf, charcode);
-  *str += ByteStringView(buf, len);
+  *str += ByteStringView(pdfium::make_span(buf).first(len));
 }
 
 WideString CPDF_Font::UnicodeFromCharCode(uint32_t charcode) const {
diff --git a/core/fpdfapi/page/cpdf_streamparser.h b/core/fpdfapi/page/cpdf_streamparser.h
index c82e9e0..ad54060 100644
--- a/core/fpdfapi/page/cpdf_streamparser.h
+++ b/core/fpdfapi/page/cpdf_streamparser.h
@@ -34,7 +34,7 @@
 
   ElementType ParseNextElement();
   ByteStringView GetWord() const {
-    return ByteStringView(m_WordBuffer.data(), m_WordSize);
+    return ByteStringView(m_WordBuffer).First(m_WordSize);
   }
   uint32_t GetPos() const { return m_Pos; }
   void SetPos(uint32_t pos) { m_Pos = pos; }
diff --git a/core/fxcrt/fx_string_unittest.cpp b/core/fxcrt/fx_string_unittest.cpp
index b1227f7..d2cf265 100644
--- a/core/fxcrt/fx_string_unittest.cpp
+++ b/core/fxcrt/fx_string_unittest.cpp
@@ -440,7 +440,7 @@
 
 TEST(fxstring, ByteStringViewSplitEfficiency) {
   std::vector<char> commas(50000, ',');
-  ByteStringView input(commas.data(), commas.size());
+  ByteStringView input(commas);
   std::vector<ByteStringView> result;
   result = fxcrt::Split(input, ',');
   ASSERT_EQ(commas.size() + 1, result.size());
@@ -460,7 +460,7 @@
 
 TEST(fxstring, WideStringViewSplitEfficiency) {
   std::vector<wchar_t> commas(50000, L',');
-  WideStringView input(commas.data(), commas.size());
+  WideStringView input(commas);
   std::vector<WideStringView> result;
   result = fxcrt::Split(input, ',');
   ASSERT_EQ(commas.size() + 1, result.size());
diff --git a/core/fxcrt/string_template.h b/core/fxcrt/string_template.h
index 55e0dc7..ace34f6 100644
--- a/core/fxcrt/string_template.h
+++ b/core/fxcrt/string_template.h
@@ -54,9 +54,7 @@
 
   // Explicit conversion to StringView.
   // Note: Any subsequent modification of |this| will invalidate the result.
-  StringView AsStringView() const {
-    return StringView(unsigned_str(), GetLength());
-  }
+  StringView AsStringView() const { return StringView(unsigned_span()); }
 
   // Explicit conversion to C-style string. The result is never nullptr,
   // and is always NUL terminated.
diff --git a/fxjs/xfa/cfxjse_formcalc_context.cpp b/fxjs/xfa/cfxjse_formcalc_context.cpp
index 3e0d4e9..d2b139f 100644
--- a/fxjs/xfa/cfxjse_formcalc_context.cpp
+++ b/fxjs/xfa/cfxjse_formcalc_context.cpp
@@ -736,7 +736,7 @@
 
 WideString EncodeHTML(const ByteString& bsHTML) {
   WideString wsHTML = WideString::FromUTF8(bsHTML.AsStringView());
-  wchar_t encode_buffer[8];
+  std::array<wchar_t, 8> encode_buffer;
   encode_buffer[0] = '&';
   encode_buffer[1] = '#';
   encode_buffer[2] = 'x';
@@ -754,7 +754,7 @@
       encode_buffer[3] = kStrCode[iIndex];
       encode_buffer[4] = kStrCode[ch - iIndex * 16];
       encode_buffer[5] = ';';
-      wsResultBuf << WideStringView(encode_buffer, 6);
+      wsResultBuf << WideStringView(encode_buffer).First(6);
     } else if (ch < 65536) {
       int32_t iBigByte = ch / 256;
       int32_t iLittleByte = ch % 256;
@@ -763,7 +763,7 @@
       encode_buffer[5] = kStrCode[iLittleByte / 16];
       encode_buffer[6] = kStrCode[iLittleByte % 16];
       encode_buffer[7] = ';';
-      wsResultBuf << WideStringView(encode_buffer, 8);
+      wsResultBuf << WideStringView(encode_buffer).First(8);
     } else {
       // TODO(tsepez): Handle codepoint not in BMP.
     }
@@ -774,7 +774,7 @@
 WideString EncodeXML(const ByteString& bsXML) {
   WideString wsXML = WideString::FromUTF8(bsXML.AsStringView());
   WideTextBuffer wsResultBuf;
-  wchar_t encode_buffer[8];
+  std::array<wchar_t, 8> encode_buffer;
   encode_buffer[0] = '&';
   encode_buffer[1] = '#';
   encode_buffer[2] = 'x';
@@ -813,7 +813,7 @@
           encode_buffer[3] = kStrCode[iIndex];
           encode_buffer[4] = kStrCode[ch - iIndex * 16];
           encode_buffer[5] = ';';
-          wsResultBuf << WideStringView(encode_buffer, 6);
+          wsResultBuf << WideStringView(encode_buffer).First(6);
         } else if (ch < 65536) {
           int32_t iBigByte = ch / 256;
           int32_t iLittleByte = ch % 256;
@@ -822,7 +822,7 @@
           encode_buffer[5] = kStrCode[iLittleByte / 16];
           encode_buffer[6] = kStrCode[iLittleByte % 16];
           encode_buffer[7] = ';';
-          wsResultBuf << WideStringView(encode_buffer, 8);
+          wsResultBuf << WideStringView(encode_buffer).First(8);
         } else {
           // TODO(tsepez): Handle codepoint not in BMP.
         }
diff --git a/xfa/fde/cfde_texteditengine.cpp b/xfa/fde/cfde_texteditengine.cpp
index d44b3f8..c5be19f 100644
--- a/xfa/fde/cfde_texteditengine.cpp
+++ b/xfa/fde/cfde_texteditengine.cpp
@@ -285,9 +285,9 @@
 
   if (validation_enabled_ || limit_horizontal_area_ || limit_vertical_area_) {
     WideString str;
-    if (gap_position_ > 0)
-      str += WideStringView(content_.data(), gap_position_);
-
+    if (gap_position_ > 0) {
+      str += WideStringView(pdfium::make_span(content_).first(gap_position_));
+    }
     str += text;
 
     if (text_length_ - gap_position_ > 0) {
@@ -876,7 +876,7 @@
 WideString CFDE_TextEditEngine::GetText() const {
   WideString str;
   if (gap_position_ > 0) {
-    str += WideStringView(content_.data(), gap_position_);
+    str += WideStringView(pdfium::make_span(content_).first(gap_position_));
   }
   if (text_length_ - gap_position_ > 0) {
     str += WideStringView(pdfium::make_span(content_).subspan(
diff --git a/xfa/fgas/crt/cfgas_stringformatter.cpp b/xfa/fgas/crt/cfgas_stringformatter.cpp
index 62e814c..ea0b6c3 100644
--- a/xfa/fgas/crt/cfgas_stringformatter.cpp
+++ b/xfa/fgas/crt/cfgas_stringformatter.cpp
@@ -440,13 +440,12 @@
       WideString wsAM = pLocale->GetMeridiemName(true);
       WideString wsPM = pLocale->GetMeridiemName(false);
       if (*cc + wsAM.GetLength() <= spTime.size() &&
-          UNSAFE_TODO(WideStringView(spTime.data() + *cc, wsAM.GetLength())) ==
-              wsAM) {
+          WideStringView(spTime.subspan(*cc, wsAM.GetLength())) == wsAM) {
         *cc += wsAM.GetLength();
         bHasA = true;
       } else if (*cc + wsPM.GetLength() <= spTime.size() &&
-                 UNSAFE_TODO(WideStringView(spTime.data() + *cc,
-                                            wsPM.GetLength())) == wsPM) {
+                 WideStringView(spTime.subspan(*cc, wsPM.GetLength())) ==
+                     wsPM) {
         *cc += wsPM.GetLength();
         bHasA = true;
         bPM = true;
@@ -953,8 +952,8 @@
     if (m_spPattern[ccf] == '\'') {
       size_t iCurChar = ccf;
       GetLiteralText(m_spPattern, &ccf);
-      wsPurgePattern += UNSAFE_TODO(
-          WideStringView(m_spPattern.data() + iCurChar, ccf - iCurChar + 1));
+      wsPurgePattern +=
+          WideStringView(m_spPattern.subspan(iCurChar, ccf - iCurChar + 1));
     } else if (!bBrackOpen &&
                !pdfium::Contains(kConstChars, m_spPattern[ccf])) {
       WideString wsSearchCategory(m_spPattern[ccf]);
@@ -1004,8 +1003,8 @@
     if (m_spPattern[ccf] == '\'') {
       size_t iCurChar = ccf;
       GetLiteralText(m_spPattern, &ccf);
-      *wsPurgePattern += UNSAFE_TODO(
-          WideStringView(m_spPattern.data() + iCurChar, ccf - iCurChar + 1));
+      *wsPurgePattern +=
+          WideStringView(m_spPattern.subspan(iCurChar, ccf - iCurChar + 1));
     } else if (!bBrackOpen &&
                !pdfium::Contains(kConstChars, m_spPattern[ccf])) {
       WideString wsCategory(m_spPattern[ccf]);
@@ -1598,8 +1597,8 @@
     if (m_spPattern[ccf] == '\'') {
       size_t iCurChar = ccf;
       GetLiteralText(m_spPattern, &ccf);
-      wsTempPattern += UNSAFE_TODO(
-          WideStringView(m_spPattern.data() + iCurChar, ccf - iCurChar + 1));
+      wsTempPattern +=
+          WideStringView(m_spPattern.subspan(iCurChar, ccf - iCurChar + 1));
     } else if (!bBraceOpen && eDateTimeType != DateTimeType::kDateTime &&
                !pdfium::Contains(kConstChars, m_spPattern[ccf])) {
       WideString wsCategory(m_spPattern[ccf]);