diff --git a/core/fpdfapi/cmaps/CNS1/cmaps_cns1.cpp b/core/fpdfapi/cmaps/CNS1/cmaps_cns1.cpp
index 810104e..a9b305e 100644
--- a/core/fpdfapi/cmaps/CNS1/cmaps_cns1.cpp
+++ b/core/fpdfapi/cmaps/CNS1/cmaps_cns1.cpp
@@ -6,7 +6,7 @@
 
 #include "core/fpdfapi/cmaps/CNS1/cmaps_cns1.h"
 
-#include "core/fxcrt/fx_memory.h"
+#include "third_party/base/stl_util.h"
 
 const FXCMAP_CMap g_FXCMAP_CNS1_cmaps[] = {
     {"B5pc-H", g_FXCMAP_B5pc_H_0, nullptr, 247, 0, FXCMAP_CMap::Range, 0},
@@ -35,4 +35,4 @@
      FXCMAP_CMap::Range, -1},
 };
 
-const size_t g_FXCMAP_CNS1_cmaps_size = FX_ArraySize(g_FXCMAP_CNS1_cmaps);
+const size_t g_FXCMAP_CNS1_cmaps_size = pdfium::size(g_FXCMAP_CNS1_cmaps);
diff --git a/core/fpdfapi/cmaps/GB1/cmaps_gb1.cpp b/core/fpdfapi/cmaps/GB1/cmaps_gb1.cpp
index a598091..fb0e46f 100644
--- a/core/fpdfapi/cmaps/GB1/cmaps_gb1.cpp
+++ b/core/fpdfapi/cmaps/GB1/cmaps_gb1.cpp
@@ -6,7 +6,7 @@
 
 #include "core/fpdfapi/cmaps/GB1/cmaps_gb1.h"
 
-#include "core/fxcrt/fx_memory.h"
+#include "third_party/base/stl_util.h"
 
 const FXCMAP_CMap g_FXCMAP_GB1_cmaps[] = {
     {"GB-EUC-H", g_FXCMAP_GB_EUC_H_0, nullptr, 90, 0, FXCMAP_CMap::Range, 0},
@@ -35,4 +35,4 @@
      FXCMAP_CMap::Range, -1},
 };
 
-const size_t g_FXCMAP_GB1_cmaps_size = FX_ArraySize(g_FXCMAP_GB1_cmaps);
+const size_t g_FXCMAP_GB1_cmaps_size = pdfium::size(g_FXCMAP_GB1_cmaps);
diff --git a/core/fpdfapi/cmaps/Japan1/cmaps_japan1.cpp b/core/fpdfapi/cmaps/Japan1/cmaps_japan1.cpp
index 5a48c77..cbb7be5 100644
--- a/core/fpdfapi/cmaps/Japan1/cmaps_japan1.cpp
+++ b/core/fpdfapi/cmaps/Japan1/cmaps_japan1.cpp
@@ -6,7 +6,7 @@
 
 #include "core/fpdfapi/cmaps/Japan1/cmaps_japan1.h"
 
-#include "core/fxcrt/fx_memory.h"
+#include "third_party/base/stl_util.h"
 
 const FXCMAP_CMap g_FXCMAP_Japan1_cmaps[] = {
     {"83pv-RKSJ-H", g_FXCMAP_83pv_RKSJ_H_1, nullptr, 222, 0, FXCMAP_CMap::Range,
@@ -47,4 +47,4 @@
      FXCMAP_CMap::Single, -1},
 };
 
-const size_t g_FXCMAP_Japan1_cmaps_size = FX_ArraySize(g_FXCMAP_Japan1_cmaps);
+const size_t g_FXCMAP_Japan1_cmaps_size = pdfium::size(g_FXCMAP_Japan1_cmaps);
diff --git a/core/fpdfapi/cmaps/Korea1/cmaps_korea1.cpp b/core/fpdfapi/cmaps/Korea1/cmaps_korea1.cpp
index 7362ff8..b28e971 100644
--- a/core/fpdfapi/cmaps/Korea1/cmaps_korea1.cpp
+++ b/core/fpdfapi/cmaps/Korea1/cmaps_korea1.cpp
@@ -6,7 +6,7 @@
 
 #include "core/fpdfapi/cmaps/Korea1/cmaps_korea1.h"
 
-#include "core/fxcrt/fx_memory.h"
+#include "third_party/base/stl_util.h"
 
 const FXCMAP_CMap g_FXCMAP_Korea1_cmaps[] = {
     {"KSC-EUC-H", g_FXCMAP_KSC_EUC_H_0, nullptr, 467, 0, FXCMAP_CMap::Range, 0},
@@ -31,4 +31,4 @@
      FXCMAP_CMap::Range, -1},
 };
 
-const size_t g_FXCMAP_Korea1_cmaps_size = FX_ArraySize(g_FXCMAP_Korea1_cmaps);
+const size_t g_FXCMAP_Korea1_cmaps_size = pdfium::size(g_FXCMAP_Korea1_cmaps);
diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
index 81ee6e8..77cafdc 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
@@ -25,6 +25,7 @@
 #include "core/fxcrt/fx_memory_wrappers.h"
 #include "core/fxge/render_defines.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/base/stl_util.h"
 
 class CPDF_PageContentGeneratorTest : public testing::Test {
  protected:
@@ -393,7 +394,7 @@
   const char content[] =
       "q 1 0 0 1 0 0 cm 3.102 4.6700001 m 5.4500012 .28999999 "
       "l 4.2399998 3.1499999 4.65 2.98 3.456 0.24 c 3.102 4.6700001 l h f Q\n";
-  size_t buf_len = FX_ArraySize(content);
+  size_t buf_len = pdfium::size(content);
   std::unique_ptr<uint8_t, FxFreeDeleter> buf(FX_AllocUninit(uint8_t, buf_len));
   memcpy(buf.get(), content, buf_len);
   auto pStream = pdfium::MakeRetain<CPDF_Stream>(std::move(buf), buf_len,
diff --git a/core/fpdfapi/font/cfx_stockfontarray.cpp b/core/fpdfapi/font/cfx_stockfontarray.cpp
index a8d8597..7e3ab6c 100644
--- a/core/fpdfapi/font/cfx_stockfontarray.cpp
+++ b/core/fpdfapi/font/cfx_stockfontarray.cpp
@@ -11,12 +11,12 @@
 
 #include "core/fpdfapi/font/cpdf_font.h"
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
-#include "core/fxcrt/fx_memory.h"
+#include "third_party/base/stl_util.h"
 
 CFX_StockFontArray::CFX_StockFontArray() = default;
 
 CFX_StockFontArray::~CFX_StockFontArray() {
-  for (size_t i = 0; i < FX_ArraySize(m_StockFonts); ++i) {
+  for (size_t i = 0; i < pdfium::size(m_StockFonts); ++i) {
     if (m_StockFonts[i]) {
       RetainPtr<CPDF_Dictionary> destroy(m_StockFonts[i]->GetFontDict());
       m_StockFonts[i]->ClearFontDict();
@@ -26,7 +26,7 @@
 
 RetainPtr<CPDF_Font> CFX_StockFontArray::GetFont(
     CFX_FontMapper::StandardFont index) const {
-  if (index < FX_ArraySize(m_StockFonts))
+  if (index < pdfium::size(m_StockFonts))
     return m_StockFonts[index];
   NOTREACHED();
   return nullptr;
@@ -34,6 +34,6 @@
 
 void CFX_StockFontArray::SetFont(CFX_FontMapper::StandardFont index,
                                  const RetainPtr<CPDF_Font>& pFont) {
-  if (index < FX_ArraySize(m_StockFonts))
+  if (index < pdfium::size(m_StockFonts))
     m_StockFonts[index] = pFont;
 }
diff --git a/core/fpdfapi/font/cpdf_cidfont.cpp b/core/fpdfapi/font/cpdf_cidfont.cpp
index 51112c5..fd1dcfa 100644
--- a/core/fpdfapi/font/cpdf_cidfont.cpp
+++ b/core/fpdfapi/font/cpdf_cidfont.cpp
@@ -21,6 +21,7 @@
 #include "core/fpdfapi/parser/cpdf_array.h"
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
 #include "core/fpdfapi/parser/cpdf_stream_acc.h"
+#include "core/fxcrt/fx_memory.h"
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxge/fx_font.h"
 #include "third_party/base/span.h"
@@ -208,7 +209,7 @@
 
 CPDF_CIDFont::CPDF_CIDFont(CPDF_Document* pDocument, CPDF_Dictionary* pFontDict)
     : CPDF_Font(pDocument, pFontDict) {
-  for (size_t i = 0; i < FX_ArraySize(m_CharBBox); ++i)
+  for (size_t i = 0; i < pdfium::size(m_CharBBox); ++i)
     m_CharBBox[i] = FX_RECT(-1, -1, -1, -1);
 }
 
@@ -836,7 +837,7 @@
   if (m_Charset != CIDSET_JAPAN1 || m_pFontFile)
     return nullptr;
 
-  const auto* pEnd = g_Japan1_VertCIDs + FX_ArraySize(g_Japan1_VertCIDs);
+  const auto* pEnd = g_Japan1_VertCIDs + pdfium::size(g_Japan1_VertCIDs);
   const auto* pTransform = std::lower_bound(
       g_Japan1_VertCIDs, pEnd, CID,
       [](const CIDTransform& entry, uint16_t cid) { return entry.cid < cid; });
diff --git a/core/fpdfapi/font/cpdf_cmapparser.cpp b/core/fpdfapi/font/cpdf_cmapparser.cpp
index d1fe51c..97e4d85 100644
--- a/core/fpdfapi/font/cpdf_cmapparser.cpp
+++ b/core/fpdfapi/font/cpdf_cmapparser.cpp
@@ -16,6 +16,7 @@
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxge/fx_freetype.h"
 #include "third_party/base/logging.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -203,10 +204,10 @@
 CIDSet CPDF_CMapParser::CharsetFromOrdering(ByteStringView ordering) {
   static const char* const kCharsetNames[CIDSET_NUM_SETS] = {
       nullptr, "GB1", "CNS1", "Japan1", "Korea1", "UCS"};
-  static_assert(FX_ArraySize(kCharsetNames) == CIDSET_NUM_SETS,
+  static_assert(pdfium::size(kCharsetNames) == CIDSET_NUM_SETS,
                 "Too many CID sets");
 
-  for (size_t charset = 1; charset < FX_ArraySize(kCharsetNames); ++charset) {
+  for (size_t charset = 1; charset < pdfium::size(kCharsetNames); ++charset) {
     if (ordering == kCharsetNames[charset])
       return static_cast<CIDSet>(charset);
   }
diff --git a/core/fpdfapi/font/cpdf_font.cpp b/core/fpdfapi/font/cpdf_font.cpp
index cbf5fdf..829f7ca 100644
--- a/core/fpdfapi/font/cpdf_font.cpp
+++ b/core/fpdfapi/font/cpdf_font.cpp
@@ -25,7 +25,6 @@
 #include "core/fpdfapi/parser/cpdf_name.h"
 #include "core/fpdfapi/parser/cpdf_stream.h"
 #include "core/fpdfapi/parser/cpdf_stream_acc.h"
-#include "core/fxcrt/fx_memory.h"
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxge/cfx_fontmapper.h"
 #include "core/fxge/fx_font.h"
@@ -316,7 +315,7 @@
   RetainPtr<CPDF_Font> pFont;
   if (type == "TrueType") {
     ByteString tag = pFontDict->GetStringFor("BaseFont").First(4);
-    for (size_t i = 0; i < FX_ArraySize(kChineseFontNames); ++i) {
+    for (size_t i = 0; i < pdfium::size(kChineseFontNames); ++i) {
       if (tag == ByteString(kChineseFontNames[i], kChineseFontNameSize)) {
         const CPDF_Dictionary* pFontDesc =
             pFontDict->GetDictFor("FontDescriptor");
diff --git a/core/fpdfapi/font/cpdf_fontencoding.cpp b/core/fpdfapi/font/cpdf_fontencoding.cpp
index 8e63e52..dd49023 100644
--- a/core/fpdfapi/font/cpdf_fontencoding.cpp
+++ b/core/fpdfapi/font/cpdf_fontencoding.cpp
@@ -16,6 +16,7 @@
 #include "core/fxge/fx_font.h"
 #include "core/fxge/fx_freetype.h"
 #include "third_party/base/ptr_util.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -1656,7 +1657,7 @@
 }  // namespace
 
 int CPDF_FontEncoding::CharCodeFromUnicode(wchar_t unicode) const {
-  for (size_t i = 0; i < FX_ArraySize(m_Unicodes); i++) {
+  for (size_t i = 0; i < pdfium::size(m_Unicodes); i++) {
     if (m_Unicodes[i] == unicode)
       return i;
   }
@@ -1666,7 +1667,7 @@
 CPDF_FontEncoding::CPDF_FontEncoding(int PredefinedEncoding) {
   const uint16_t* pSrc = PDF_UnicodesForPredefinedCharSet(PredefinedEncoding);
   if (pSrc) {
-    for (size_t i = 0; i < FX_ArraySize(m_Unicodes); i++)
+    for (size_t i = 0; i < pdfium::size(m_Unicodes); i++)
       m_Unicodes[i] = pSrc[i];
   } else {
     memset(m_Unicodes, 0, sizeof(m_Unicodes));
@@ -1684,7 +1685,7 @@
        cs++) {
     const uint16_t* pSrc = PDF_UnicodesForPredefinedCharSet(cs);
     bool match = true;
-    for (size_t i = 0; i < FX_ArraySize(m_Unicodes); i++) {
+    for (size_t i = 0; i < pdfium::size(m_Unicodes); i++) {
       if (m_Unicodes[i] != pSrc[i]) {
         match = false;
         break;
@@ -1711,7 +1712,7 @@
   const uint16_t* pStandard =
       PDF_UnicodesForPredefinedCharSet(PDFFONT_ENCODING_WINANSI);
   auto pDiff = pdfium::MakeRetain<CPDF_Array>();
-  for (size_t i = 0; i < FX_ArraySize(m_Unicodes); i++) {
+  for (size_t i = 0; i < pdfium::size(m_Unicodes); i++) {
     if (pStandard[i] == m_Unicodes[i])
       continue;
 
diff --git a/core/fpdfapi/font/cpdf_simplefont.cpp b/core/fpdfapi/font/cpdf_simplefont.cpp
index c0fd4e0..29f2861 100644
--- a/core/fpdfapi/font/cpdf_simplefont.cpp
+++ b/core/fpdfapi/font/cpdf_simplefont.cpp
@@ -12,6 +12,7 @@
 #include "core/fxge/fx_font.h"
 #include "core/fxge/fx_freetype.h"
 #include "third_party/base/numerics/safe_math.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -33,7 +34,7 @@
     : CPDF_Font(pDocument, pFontDict) {
   memset(m_CharWidth, 0xff, sizeof(m_CharWidth));
   memset(m_GlyphIndex, 0xff, sizeof(m_GlyphIndex));
-  for (size_t i = 0; i < FX_ArraySize(m_CharBBox); ++i)
+  for (size_t i = 0; i < pdfium::size(m_CharBBox); ++i)
     m_CharBBox[i] = FX_RECT(-1, -1, -1, -1);
 }
 
@@ -228,7 +229,7 @@
   if (FontStyleIsAllCaps(m_Flags)) {
     static const unsigned char kLowercases[][2] = {
         {'a', 'z'}, {0xe0, 0xf6}, {0xf8, 0xfd}};
-    for (size_t range = 0; range < FX_ArraySize(kLowercases); ++range) {
+    for (size_t range = 0; range < pdfium::size(kLowercases); ++range) {
       const auto& lower = kLowercases[range];
       for (int i = lower[0]; i <= lower[1]; ++i) {
         if (m_GlyphIndex[i] != 0xffff && m_pFontFile)
diff --git a/core/fpdfapi/font/cpdf_truetypefont.cpp b/core/fpdfapi/font/cpdf_truetypefont.cpp
index d107ed0..a02b872 100644
--- a/core/fpdfapi/font/cpdf_truetypefont.cpp
+++ b/core/fpdfapi/font/cpdf_truetypefont.cpp
@@ -8,6 +8,7 @@
 
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
 #include "core/fxge/fx_font.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -106,7 +107,7 @@
       }
       m_Encoding.SetUnicode(charcode, PDF_UnicodeFromAdobeName(name));
       if (bMSSymbol) {
-        for (size_t j = 0; j < FX_ArraySize(kPrefix); j++) {
+        for (size_t j = 0; j < pdfium::size(kPrefix); j++) {
           uint16_t unicode = kPrefix[j] * 256 + charcode;
           m_GlyphIndex[charcode] = FT_Get_Char_Index(face, unicode);
           if (m_GlyphIndex[charcode])
@@ -150,7 +151,7 @@
   if (FT_UseTTCharmap(face, 3, 0)) {
     bool bFound = false;
     for (int charcode = 0; charcode < 256; charcode++) {
-      for (size_t j = 0; j < FX_ArraySize(kPrefix); j++) {
+      for (size_t j = 0; j < pdfium::size(kPrefix); j++) {
         uint16_t unicode = kPrefix[j] * 256 + charcode;
         m_GlyphIndex[charcode] = FT_Get_Char_Index(face, unicode);
         if (m_GlyphIndex[charcode]) {
diff --git a/core/fpdfapi/font/cpdf_type3font.cpp b/core/fpdfapi/font/cpdf_type3font.cpp
index a49f177..124245d 100644
--- a/core/fpdfapi/font/cpdf_type3font.cpp
+++ b/core/fpdfapi/font/cpdf_type3font.cpp
@@ -16,6 +16,7 @@
 #include "core/fpdfapi/parser/cpdf_stream.h"
 #include "core/fxcrt/autorestorer.h"
 #include "core/fxcrt/fx_system.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -148,7 +149,7 @@
 }
 
 uint32_t CPDF_Type3Font::GetCharWidthF(uint32_t charcode) {
-  if (charcode >= FX_ArraySize(m_CharWidthL))
+  if (charcode >= pdfium::size(m_CharWidthL))
     charcode = 0;
 
   if (m_CharWidthL[charcode])
diff --git a/core/fpdfapi/page/cpdf_colorspace.cpp b/core/fpdfapi/page/cpdf_colorspace.cpp
index 6b309cb..f6e26e7 100644
--- a/core/fpdfapi/page/cpdf_colorspace.cpp
+++ b/core/fpdfapi/page/cpdf_colorspace.cpp
@@ -31,7 +31,6 @@
 #include "core/fpdfapi/parser/fpdf_parser_utility.h"
 #include "core/fxcodec/fx_codec.h"
 #include "core/fxcodec/icc/iccmodule.h"
-#include "core/fxcrt/fx_memory.h"
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxcrt/maybe_owned.h"
 #include "third_party/base/stl_util.h"
@@ -737,14 +736,14 @@
   const CPDF_Array* pParam = pDict->GetArrayFor("Gamma");
   if (pParam) {
     m_bHasGamma = true;
-    for (size_t i = 0; i < FX_ArraySize(m_Gamma); ++i)
+    for (size_t i = 0; i < pdfium::size(m_Gamma); ++i)
       m_Gamma[i] = pParam->GetNumberAt(i);
   }
 
   pParam = pDict->GetArrayFor("Matrix");
   if (pParam) {
     m_bHasMatrix = true;
-    for (size_t i = 0; i < FX_ArraySize(m_Matrix); ++i)
+    for (size_t i = 0; i < pdfium::size(m_Matrix); ++i)
       m_Matrix[i] = pParam->GetNumberAt(i);
   }
   return 3;
@@ -844,9 +843,9 @@
   static constexpr float kDefaultRanges[kRangesCount] = {-100.0f, 100.0f,
                                                          -100.0f, 100.0f};
   static_assert(
-      FX_ArraySize(kDefaultRanges) == std::extent<decltype(m_Ranges)>(),
+      pdfium::size(kDefaultRanges) == std::extent<decltype(m_Ranges)>(),
       "Range size mismatch");
-  for (size_t i = 0; i < FX_ArraySize(kDefaultRanges); ++i)
+  for (size_t i = 0; i < pdfium::size(kDefaultRanges); ++i)
     m_Ranges[i] = pParam ? pParam->GetNumberAt(i) : kDefaultRanges[i];
   return 3;
 }
diff --git a/core/fpdfapi/page/cpdf_docpagedata.cpp b/core/fpdfapi/page/cpdf_docpagedata.cpp
index a242e35..d6958ac 100644
--- a/core/fpdfapi/page/cpdf_docpagedata.cpp
+++ b/core/fpdfapi/page/cpdf_docpagedata.cpp
@@ -30,6 +30,7 @@
 #include "core/fpdfapi/parser/cpdf_stream_acc.h"
 #include "core/fpdfapi/parser/cpdf_string.h"
 #include "core/fxcrt/fx_codepage.h"
+#include "core/fxcrt/fx_memory.h"
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxge/cfx_font.h"
 #include "core/fxge/cfx_fontmapper.h"
@@ -485,7 +486,7 @@
       }
     } else {
       size_t i = CalculateEncodingDict(charset, pBaseDict);
-      if (i < FX_ArraySize(g_FX_CharsetUnicodes)) {
+      if (i < pdfium::size(g_FX_CharsetUnicodes)) {
         const uint16_t* pUnicodes = g_FX_CharsetUnicodes[i].m_pUnicodes;
         for (int j = 0; j < 128; j++) {
           int glyph_index = pEncoding->GlyphFromCharCode(pUnicodes[j]);
@@ -516,7 +517,7 @@
     nStemV = pFont->GetSubstFont()->m_Weight / 5;
   } else {
     static const char stem_chars[] = {'i', 'I', '!', '1'};
-    const size_t count = FX_ArraySize(stem_chars);
+    const size_t count = pdfium::size(stem_chars);
     uint32_t glyph = pEncoding->GlyphFromCharCode(stem_chars[0]);
     nStemV = pFont->GetGlyphWidth(glyph);
     for (size_t i = 1; i < count; i++) {
@@ -621,11 +622,11 @@
 size_t CPDF_DocPageData::CalculateEncodingDict(int charset,
                                                CPDF_Dictionary* pBaseDict) {
   size_t i;
-  for (i = 0; i < FX_ArraySize(g_FX_CharsetUnicodes); ++i) {
+  for (i = 0; i < pdfium::size(g_FX_CharsetUnicodes); ++i) {
     if (g_FX_CharsetUnicodes[i].m_Charset == charset)
       break;
   }
-  if (i == FX_ArraySize(g_FX_CharsetUnicodes))
+  if (i == pdfium::size(g_FX_CharsetUnicodes))
     return i;
 
   CPDF_Dictionary* pEncodingDict =
diff --git a/core/fpdfapi/page/cpdf_psengine_unittest.cpp b/core/fpdfapi/page/cpdf_psengine_unittest.cpp
index 2d4ddb5..85c77c8 100644
--- a/core/fpdfapi/page/cpdf_psengine_unittest.cpp
+++ b/core/fpdfapi/page/cpdf_psengine_unittest.cpp
@@ -5,8 +5,8 @@
 #include <limits>
 
 #include "core/fpdfapi/page/cpdf_psengine.h"
-#include "core/fxcrt/fx_memory.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -71,7 +71,7 @@
 
   CPDF_PSProc proc;
   EXPECT_EQ(0U, proc.num_operators());
-  for (size_t i = 0; i < FX_ArraySize(kTestData); ++i) {
+  for (size_t i = 0; i < pdfium::size(kTestData); ++i) {
     ByteStringView word(kTestData[i].name);
     proc.AddOperatorForTesting(word);
     ASSERT_EQ(i + 1, proc.num_operators());
diff --git a/core/fpdfapi/page/cpdf_streamcontentparser.cpp b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
index 5d2e429..2ac0a7b 100644
--- a/core/fpdfapi/page/cpdf_streamcontentparser.cpp
+++ b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
@@ -182,7 +182,7 @@
       ByteString key = it.first;
       CPDF_Object* value = it.second.Get();
       ByteStringView fullname = FindFullName(
-          kInlineKeyAbbr, FX_ArraySize(kInlineKeyAbbr), key.AsStringView());
+          kInlineKeyAbbr, pdfium::size(kInlineKeyAbbr), key.AsStringView());
       if (!fullname.IsEmpty()) {
         AbbrReplacementOp op;
         op.is_replace_key = true;
@@ -195,7 +195,7 @@
       if (value->IsName()) {
         ByteString name = value->GetString();
         fullname =
-            FindFullName(kInlineValueAbbr, FX_ArraySize(kInlineValueAbbr),
+            FindFullName(kInlineValueAbbr, pdfium::size(kInlineValueAbbr),
                          name.AsStringView());
         if (!fullname.IsEmpty()) {
           AbbrReplacementOp op;
@@ -223,7 +223,7 @@
     if (pElement->IsName()) {
       ByteString name = pElement->GetString();
       ByteStringView fullname =
-          FindFullName(kInlineValueAbbr, FX_ArraySize(kInlineValueAbbr),
+          FindFullName(kInlineValueAbbr, pdfium::size(kInlineValueAbbr),
                        name.AsStringView());
       if (!fullname.IsEmpty())
         pArray->SetNewAt<CPDF_Name>(i, ByteString(fullname));
@@ -1630,13 +1630,13 @@
 // static
 ByteStringView CPDF_StreamContentParser::FindKeyAbbreviationForTesting(
     ByteStringView abbr) {
-  return FindFullName(kInlineKeyAbbr, FX_ArraySize(kInlineKeyAbbr), abbr);
+  return FindFullName(kInlineKeyAbbr, pdfium::size(kInlineKeyAbbr), abbr);
 }
 
 // static
 ByteStringView CPDF_StreamContentParser::FindValueAbbreviationForTesting(
     ByteStringView abbr) {
-  return FindFullName(kInlineValueAbbr, FX_ArraySize(kInlineValueAbbr), abbr);
+  return FindFullName(kInlineValueAbbr, pdfium::size(kInlineValueAbbr), abbr);
 }
 
 CPDF_StreamContentParser::ContentParam::ContentParam() {}
diff --git a/core/fpdfapi/parser/cpdf_array_unittest.cpp b/core/fpdfapi/parser/cpdf_array_unittest.cpp
index aea94d1..23b3f5c 100644
--- a/core/fpdfapi/parser/cpdf_array_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_array_unittest.cpp
@@ -10,8 +10,8 @@
 #include "core/fpdfapi/parser/cpdf_boolean.h"
 #include "core/fpdfapi/parser/cpdf_number.h"
 #include "core/fpdfapi/parser/cpdf_reference.h"
-#include "core/fxcrt/fx_memory.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/base/stl_util.h"
 
 TEST(cpdf_array, GetBooleanAt) {
   auto arr = pdfium::MakeRetain<CPDF_Array>();
@@ -37,29 +37,29 @@
   {
     const int elems[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+    for (size_t i = 0; i < pdfium::size(elems); ++i)
       arr->AppendNew<CPDF_Number>(elems[i]);
     for (size_t i = 0; i < 3; ++i)
       arr->RemoveAt(3);
     const int expected[] = {1, 2, 3, 7, 8, 9, 10};
-    ASSERT_EQ(FX_ArraySize(expected), arr->size());
-    for (size_t i = 0; i < FX_ArraySize(expected); ++i)
+    ASSERT_EQ(pdfium::size(expected), arr->size());
+    for (size_t i = 0; i < pdfium::size(expected); ++i)
       EXPECT_EQ(expected[i], arr->GetIntegerAt(i));
     arr->RemoveAt(4);
     arr->RemoveAt(4);
     const int expected2[] = {1, 2, 3, 7, 10};
-    ASSERT_EQ(FX_ArraySize(expected2), arr->size());
-    for (size_t i = 0; i < FX_ArraySize(expected2); ++i)
+    ASSERT_EQ(pdfium::size(expected2), arr->size());
+    for (size_t i = 0; i < pdfium::size(expected2); ++i)
       EXPECT_EQ(expected2[i], arr->GetIntegerAt(i));
   }
   {
     // When the range is out of bound, RemoveAt() has no effect.
     const int elems[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+    for (size_t i = 0; i < pdfium::size(elems); ++i)
       arr->AppendNew<CPDF_Number>(elems[i]);
     arr->RemoveAt(11);
-    EXPECT_EQ(FX_ArraySize(elems), arr->size());
+    EXPECT_EQ(pdfium::size(elems), arr->size());
   }
 }
 
@@ -67,9 +67,9 @@
   const int elems[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
   auto arr = pdfium::MakeRetain<CPDF_Array>();
   EXPECT_EQ(0U, arr->size());
-  for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+  for (size_t i = 0; i < pdfium::size(elems); ++i)
     arr->AppendNew<CPDF_Number>(elems[i]);
-  EXPECT_EQ(FX_ArraySize(elems), arr->size());
+  EXPECT_EQ(pdfium::size(elems), arr->size());
   arr->Clear();
   EXPECT_EQ(0U, arr->size());
 }
@@ -78,17 +78,17 @@
   {
     const int elems[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+    for (size_t i = 0; i < pdfium::size(elems); ++i)
       arr->InsertNewAt<CPDF_Number>(i, elems[i]);
-    ASSERT_EQ(FX_ArraySize(elems), arr->size());
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+    ASSERT_EQ(pdfium::size(elems), arr->size());
+    for (size_t i = 0; i < pdfium::size(elems); ++i)
       EXPECT_EQ(elems[i], arr->GetIntegerAt(i));
     arr->InsertNewAt<CPDF_Number>(3, 33);
     arr->InsertNewAt<CPDF_Number>(6, 55);
     arr->InsertNewAt<CPDF_Number>(12, 12);
     const int expected[] = {1, 2, 3, 33, 4, 5, 55, 6, 7, 8, 9, 10, 12};
-    ASSERT_EQ(FX_ArraySize(expected), arr->size());
-    for (size_t i = 0; i < FX_ArraySize(expected); ++i)
+    ASSERT_EQ(pdfium::size(expected), arr->size());
+    for (size_t i = 0; i < pdfium::size(expected); ++i)
       EXPECT_EQ(expected[i], arr->GetIntegerAt(i));
   }
   {
@@ -97,13 +97,13 @@
     // positions have nullptr.
     const int elems[] = {1, 2};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+    for (size_t i = 0; i < pdfium::size(elems); ++i)
       arr->InsertNewAt<CPDF_Number>(i, elems[i]);
     arr->InsertNewAt<CPDF_Number>(10, 10);
     ASSERT_EQ(11u, arr->size());
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+    for (size_t i = 0; i < pdfium::size(elems); ++i)
       EXPECT_EQ(elems[i], arr->GetIntegerAt(i));
-    for (size_t i = FX_ArraySize(elems); i < 10; ++i)
+    for (size_t i = pdfium::size(elems); i < 10; ++i)
       EXPECT_EQ(nullptr, arr->GetObjectAt(i));
     EXPECT_EQ(10, arr->GetIntegerAt(10));
   }
@@ -114,11 +114,11 @@
     // Basic case.
     const int elems[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+    for (size_t i = 0; i < pdfium::size(elems); ++i)
       arr->InsertNewAt<CPDF_Number>(i, elems[i]);
     RetainPtr<CPDF_Array> arr2 = ToArray(arr->Clone());
     ASSERT_EQ(arr->size(), arr2->size());
-    for (size_t i = 0; i < FX_ArraySize(elems); ++i) {
+    for (size_t i = 0; i < pdfium::size(elems); ++i) {
       // Clone() always create new objects.
       EXPECT_NE(arr->GetObjectAt(i), arr2->GetObjectAt(i));
       EXPECT_EQ(arr->GetIntegerAt(i), arr2->GetIntegerAt(i));
@@ -196,12 +196,12 @@
   const int elems[] = {-23, -11,     3,         455,   2345877,
                        0,   7895330, -12564334, 10000, -100000};
   auto arr = pdfium::MakeRetain<CPDF_Array>();
-  for (size_t i = 0; i < FX_ArraySize(elems); ++i)
+  for (size_t i = 0; i < pdfium::size(elems); ++i)
     arr->InsertNewAt<CPDF_Number>(i, elems[i]);
   size_t index = 0;
 
   CPDF_ArrayLocker locker(arr.Get());
   for (const auto& it : locker)
     EXPECT_EQ(elems[index++], it->AsNumber()->GetInteger());
-  EXPECT_EQ(FX_ArraySize(elems), index);
+  EXPECT_EQ(pdfium::size(elems), index);
 }
diff --git a/core/fpdfapi/parser/cpdf_object_unittest.cpp b/core/fpdfapi/parser/cpdf_object_unittest.cpp
index 4930e9c..eb82036 100644
--- a/core/fpdfapi/parser/cpdf_object_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_object_unittest.cpp
@@ -23,6 +23,7 @@
 #include "core/fpdfapi/parser/cpdf_string.h"
 #include "core/fxcrt/fx_memory_wrappers.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -71,7 +72,7 @@
     m_DictObj->SetNewFor<CPDF_Number>("num", 0.23f);
     // Stream object.
     const char content[] = "abcdefghijklmnopqrstuvwxyz";
-    size_t buf_len = FX_ArraySize(content);
+    size_t buf_len = pdfium::size(content);
     std::unique_ptr<uint8_t, FxFreeDeleter> buf(
         FX_AllocUninit(uint8_t, buf_len));
     memcpy(buf.get(), content, buf_len);
@@ -94,7 +95,7 @@
         CPDF_Object::kNumber,  CPDF_Object::kString,  CPDF_Object::kString,
         CPDF_Object::kName,    CPDF_Object::kArray,   CPDF_Object::kDictionary,
         CPDF_Object::kStream,  CPDF_Object::kNullobj};
-    for (size_t i = 0; i < FX_ArraySize(objs); ++i)
+    for (size_t i = 0; i < pdfium::size(objs); ++i)
       m_DirectObjs.emplace_back(objs[i]);
 
     // Indirect references to indirect objects.
@@ -323,7 +324,7 @@
                                     "changed", "",     "NewName"};
   const char* const expected[] = {"true",    "false", "3.125",  "97",
                                   "changed", "",      "NewName"};
-  for (size_t i = 0; i < FX_ArraySize(set_values); ++i) {
+  for (size_t i = 0; i < pdfium::size(set_values); ++i) {
     m_DirectObjs[i]->SetString(set_values[i]);
     EXPECT_STREQ(expected[i], m_DirectObjs[i]->GetString().c_str());
   }
@@ -415,7 +416,7 @@
                       {1, 2, 3, 4, 5, 6},
                       {2.3f, 4.05f, 3, -2, -3, 0.0f},
                       {0.05f, 0.1f, 0.56f, 0.67f, 1.34f, 99.9f}};
-  for (size_t i = 0; i < FX_ArraySize(elems); ++i) {
+  for (size_t i = 0; i < pdfium::size(elems); ++i) {
     auto arr = pdfium::MakeRetain<CPDF_Array>();
     CFX_Matrix matrix(elems[i][0], elems[i][1], elems[i][2], elems[i][3],
                       elems[i][4], elems[i][5]);
@@ -436,7 +437,7 @@
                       {1, 2, 5, 6},
                       {2.3f, 4.05f, -3, 0.0f},
                       {0.05f, 0.1f, 1.34f, 99.9f}};
-  for (size_t i = 0; i < FX_ArraySize(elems); ++i) {
+  for (size_t i = 0; i < pdfium::size(elems); ++i) {
     auto arr = pdfium::MakeRetain<CPDF_Array>();
     CFX_FloatRect rect(elems[i]);
     for (size_t j = 0; j < 4; ++j)
@@ -454,9 +455,9 @@
     // Boolean array.
     const bool vals[] = {true, false, false, true, true};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i)
+    for (size_t i = 0; i < pdfium::size(vals); ++i)
       arr->InsertNewAt<CPDF_Boolean>(i, vals[i]);
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i) {
+    for (size_t i = 0; i < pdfium::size(vals); ++i) {
       TestArrayAccessors(arr.Get(), i,                // Array and index.
                          vals[i] ? "true" : "false",  // String value.
                          nullptr,                     // Const string value.
@@ -471,9 +472,9 @@
     // Integer array.
     const int vals[] = {10, 0, -345, 2089345456, -1000000000, 567, 93658767};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i)
+    for (size_t i = 0; i < pdfium::size(vals); ++i)
       arr->InsertNewAt<CPDF_Number>(i, vals[i]);
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i) {
+    for (size_t i = 0; i < pdfium::size(vals); ++i) {
       char buf[33];
       TestArrayAccessors(arr.Get(), i,                  // Array and index.
                          FXSYS_itoa(vals[i], buf, 10),  // String value.
@@ -492,9 +493,9 @@
     const char* const expected_str[] = {
         "0", "0", "10", "10", "0.0345", "897.34", "-2.5", "-1", "-345", "0"};
     auto arr = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i)
+    for (size_t i = 0; i < pdfium::size(vals); ++i)
       arr->InsertNewAt<CPDF_Number>(i, vals[i]);
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i) {
+    for (size_t i = 0; i < pdfium::size(vals); ++i) {
       TestArrayAccessors(arr.Get(), i,     // Array and index.
                          expected_str[i],  // String value.
                          nullptr,          // Const string value.
@@ -511,11 +512,11 @@
                                 ".",    "EYREW",    "It is a joke :)"};
     auto string_array = pdfium::MakeRetain<CPDF_Array>();
     auto name_array = pdfium::MakeRetain<CPDF_Array>();
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i) {
+    for (size_t i = 0; i < pdfium::size(vals); ++i) {
       string_array->InsertNewAt<CPDF_String>(i, vals[i], false);
       name_array->InsertNewAt<CPDF_Name>(i, vals[i]);
     }
-    for (size_t i = 0; i < FX_ArraySize(vals); ++i) {
+    for (size_t i = 0; i < pdfium::size(vals); ++i) {
       TestArrayAccessors(string_array.Get(), i,  // Array and index.
                          vals[i],                // String value.
                          vals[i],                // Const string value.
@@ -612,7 +613,7 @@
         vals[i]->SetNewFor<CPDF_Number>(key.c_str(), value);
       }
       uint8_t content[] = "content: this is a stream";
-      size_t data_size = FX_ArraySize(content);
+      size_t data_size = pdfium::size(content);
       std::unique_ptr<uint8_t, FxFreeDeleter> data(
           FX_AllocUninit(uint8_t, data_size));
       memcpy(data.get(), content, data_size);
@@ -698,9 +699,9 @@
   float vals[] = {1.0f,         -1.0f, 0,    0.456734f,
                   12345.54321f, 0.5f,  1000, 0.000045f};
   auto arr = pdfium::MakeRetain<CPDF_Array>();
-  for (size_t i = 0; i < FX_ArraySize(vals); ++i)
+  for (size_t i = 0; i < pdfium::size(vals); ++i)
     arr->AppendNew<CPDF_Number>(vals[i]);
-  for (size_t i = 0; i < FX_ArraySize(vals); ++i) {
+  for (size_t i = 0; i < pdfium::size(vals); ++i) {
     EXPECT_EQ(CPDF_Object::kNumber, arr->GetObjectAt(i)->GetType());
     EXPECT_EQ(vals[i], arr->GetObjectAt(i)->GetNumber());
   }
@@ -709,9 +710,9 @@
 TEST(PDFArrayTest, AddInteger) {
   int vals[] = {0, 1, 934435456, 876, 10000, -1, -24354656, -100};
   auto arr = pdfium::MakeRetain<CPDF_Array>();
-  for (size_t i = 0; i < FX_ArraySize(vals); ++i)
+  for (size_t i = 0; i < pdfium::size(vals); ++i)
     arr->AppendNew<CPDF_Number>(vals[i]);
-  for (size_t i = 0; i < FX_ArraySize(vals); ++i) {
+  for (size_t i = 0; i < pdfium::size(vals); ++i) {
     EXPECT_EQ(CPDF_Object::kNumber, arr->GetObjectAt(i)->GetType());
     EXPECT_EQ(vals[i], arr->GetObjectAt(i)->GetNumber());
   }
@@ -727,7 +728,7 @@
     string_array->AppendNew<CPDF_String>(val, false);
     name_array->AppendNew<CPDF_Name>(val);
   }
-  for (size_t i = 0; i < FX_ArraySize(kVals); ++i) {
+  for (size_t i = 0; i < pdfium::size(kVals); ++i) {
     EXPECT_EQ(CPDF_Object::kString, string_array->GetObjectAt(i)->GetType());
     EXPECT_STREQ(kVals[i], string_array->GetObjectAt(i)->GetString().c_str());
     EXPECT_EQ(CPDF_Object::kName, name_array->GetObjectAt(i)->GetType());
@@ -750,7 +751,7 @@
   auto arr = pdfium::MakeRetain<CPDF_Array>();
   auto arr1 = pdfium::MakeRetain<CPDF_Array>();
   // Create two arrays of references by different AddReference() APIs.
-  for (size_t i = 0; i < FX_ArraySize(indirect_objs); ++i) {
+  for (size_t i = 0; i < pdfium::size(indirect_objs); ++i) {
     holder->ReplaceIndirectObjectIfHigherGeneration(obj_nums[i],
                                                     indirect_objs[i]);
     arr->AppendNew<CPDF_Reference>(holder.get(), obj_nums[i]);
@@ -758,7 +759,7 @@
                                     indirect_objs[i]->GetObjNum());
   }
   // Check indirect objects.
-  for (size_t i = 0; i < FX_ArraySize(obj_nums); ++i)
+  for (size_t i = 0; i < pdfium::size(obj_nums); ++i)
     EXPECT_EQ(indirect_objs[i], holder->GetOrParseIndirectObject(obj_nums[i]));
   // Check arrays.
   EXPECT_EQ(arr->size(), arr1->size());
diff --git a/core/fpdfapi/parser/cpdf_parser_unittest.cpp b/core/fpdfapi/parser/cpdf_parser_unittest.cpp
index f69416e..c888b46 100644
--- a/core/fpdfapi/parser/cpdf_parser_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_parser_unittest.cpp
@@ -18,6 +18,7 @@
 #include "core/fxcrt/retain_ptr.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/utils/path_service.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -79,9 +80,9 @@
   ASSERT_TRUE(parser.RebuildCrossRef());
   const FX_FILESIZE offsets[] = {0, 15, 61, 154, 296, 374, 450};
   const uint16_t versions[] = {0, 0, 2, 4, 6, 8, 0};
-  for (size_t i = 0; i < FX_ArraySize(offsets); ++i)
+  for (size_t i = 0; i < pdfium::size(offsets); ++i)
     EXPECT_EQ(offsets[i], GetObjInfo(parser, i).pos);
-  for (size_t i = 0; i < FX_ArraySize(versions); ++i)
+  for (size_t i = 0; i < pdfium::size(versions); ++i)
     EXPECT_EQ(versions[i], GetObjInfo(parser, i).gennum);
 }
 
@@ -119,9 +120,9 @@
         CPDF_TestParser::ObjectType::kFree,
         CPDF_TestParser::ObjectType::kNotCompressed,
         CPDF_TestParser::ObjectType::kNotCompressed};
-    static_assert(FX_ArraySize(kOffsets) == FX_ArraySize(kTypes),
+    static_assert(pdfium::size(kOffsets) == pdfium::size(kTypes),
                   "kOffsets / kTypes size mismatch");
-    for (size_t i = 0; i < FX_ArraySize(kOffsets); ++i) {
+    for (size_t i = 0; i < pdfium::size(kOffsets); ++i) {
       EXPECT_EQ(kOffsets[i], GetObjInfo(parser, i).pos);
       EXPECT_EQ(kTypes[i], GetObjInfo(parser, i).type);
     }
@@ -159,9 +160,9 @@
         CPDF_TestParser::ObjectType::kFree,
         CPDF_TestParser::ObjectType::kFree,
         CPDF_TestParser::ObjectType::kNotCompressed};
-    static_assert(FX_ArraySize(kOffsets) == FX_ArraySize(kTypes),
+    static_assert(pdfium::size(kOffsets) == pdfium::size(kTypes),
                   "kOffsets / kTypes size mismatch");
-    for (size_t i = 0; i < FX_ArraySize(kOffsets); ++i) {
+    for (size_t i = 0; i < pdfium::size(kOffsets); ++i) {
       EXPECT_EQ(kOffsets[i], GetObjInfo(parser, i).pos);
       EXPECT_EQ(kTypes[i], GetObjInfo(parser, i).type);
     }
@@ -199,9 +200,9 @@
         CPDF_TestParser::ObjectType::kFree,
         CPDF_TestParser::ObjectType::kFree,
         CPDF_TestParser::ObjectType::kNotCompressed};
-    static_assert(FX_ArraySize(kOffsets) == FX_ArraySize(kTypes),
+    static_assert(pdfium::size(kOffsets) == pdfium::size(kTypes),
                   "kOffsets / kTypes size mismatch");
-    for (size_t i = 0; i < FX_ArraySize(kOffsets); ++i) {
+    for (size_t i = 0; i < pdfium::size(kOffsets); ++i) {
       EXPECT_EQ(kOffsets[i], GetObjInfo(parser, i).pos);
       EXPECT_EQ(kTypes[i], GetObjInfo(parser, i).type);
     }
@@ -231,9 +232,9 @@
         CPDF_TestParser::ObjectType::kFree,
         CPDF_TestParser::ObjectType::kNotCompressed,
         CPDF_TestParser::ObjectType::kNotCompressed};
-    static_assert(FX_ArraySize(kOffsets) == FX_ArraySize(kTypes),
+    static_assert(pdfium::size(kOffsets) == pdfium::size(kTypes),
                   "kOffsets / kTypes size mismatch");
-    for (size_t i = 0; i < FX_ArraySize(kOffsets); ++i) {
+    for (size_t i = 0; i < pdfium::size(kOffsets); ++i) {
       EXPECT_EQ(kOffsets[i], GetObjInfo(parser, i).pos);
       EXPECT_EQ(kTypes[i], GetObjInfo(parser, i).type);
     }
diff --git a/core/fpdfapi/parser/cpdf_security_handler.cpp b/core/fpdfapi/parser/cpdf_security_handler.cpp
index e1e8c77..81533c9 100644
--- a/core/fpdfapi/parser/cpdf_security_handler.cpp
+++ b/core/fpdfapi/parser/cpdf_security_handler.cpp
@@ -19,6 +19,7 @@
 #include "core/fpdfapi/parser/cpdf_object.h"
 #include "core/fpdfapi/parser/cpdf_string.h"
 #include "core/fxcrt/fx_random.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -551,7 +552,7 @@
 
   if (m_Revision >= 5) {
     uint32_t random[4];
-    FX_Random_GenerateMT(random, FX_ArraySize(random));
+    FX_Random_GenerateMT(random, pdfium::size(random));
     CRYPT_sha2_context sha;
     CRYPT_SHA256Start(&sha);
     CRYPT_SHA256Update(&sha, reinterpret_cast<uint8_t*>(random),
diff --git a/core/fpdfapi/parser/cpdf_simple_parser_unittest.cpp b/core/fpdfapi/parser/cpdf_simple_parser_unittest.cpp
index a8411a3..98dbe17 100644
--- a/core/fpdfapi/parser/cpdf_simple_parser_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_simple_parser_unittest.cpp
@@ -7,10 +7,10 @@
 #include <string>
 
 #include "core/fpdfapi/parser/fpdf_parser_utility.h"
-#include "core/fxcrt/fx_memory.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/test_support.h"
 #include "third_party/base/span.h"
+#include "third_party/base/stl_util.h"
 
 TEST(SimpleParserTest, GetWord) {
   static const pdfium::StrFuncTestData test_data[] = {
@@ -51,7 +51,7 @@
       STR_IN_OUT_CASE(" $^&&*\t\0sdff ", "$^&&*"),
       STR_IN_OUT_CASE("\n\r+3.5656 -11.0", "+3.5656"),
   };
-  for (size_t i = 0; i < FX_ArraySize(test_data); ++i) {
+  for (size_t i = 0; i < pdfium::size(test_data); ++i) {
     const pdfium::StrFuncTestData& data = test_data[i];
     CPDF_SimpleParser parser(pdfium::make_span(data.input, data.input_size));
     ByteStringView word = parser.GetWord();
diff --git a/core/fpdfapi/parser/fpdf_parser_decode_unittest.cpp b/core/fpdfapi/parser/fpdf_parser_decode_unittest.cpp
index 45f1593..bd1b423 100644
--- a/core/fpdfapi/parser/fpdf_parser_decode_unittest.cpp
+++ b/core/fpdfapi/parser/fpdf_parser_decode_unittest.cpp
@@ -11,6 +11,7 @@
 #include "core/fxcrt/fx_memory_wrappers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/test_support.h"
+#include "third_party/base/stl_util.h"
 
 TEST(fpdf_parser_decode, ValidateDecoderPipeline) {
   {
@@ -238,7 +239,7 @@
           96),
   };
 
-  for (size_t i = 0; i < FX_ArraySize(flate_decode_cases); ++i) {
+  for (size_t i = 0; i < pdfium::size(flate_decode_cases); ++i) {
     const pdfium::DecodeTestData& data = flate_decode_cases[i];
     std::unique_ptr<uint8_t, FxFreeDeleter> buf;
     uint32_t buf_size;
@@ -272,7 +273,7 @@
           "\x2b\x58\x1a\x9a\x83\x8c\x49\xe3\x0a\x04\x42\x00\x37\x4c\x1b\x42"),
   };
 
-  for (size_t i = 0; i < FX_ArraySize(flate_encode_cases); ++i) {
+  for (size_t i = 0; i < pdfium::size(flate_encode_cases); ++i) {
     const pdfium::StrFuncTestData& data = flate_encode_cases[i];
     std::unique_ptr<uint8_t, FxFreeDeleter> buf;
     uint32_t buf_size;
diff --git a/core/fpdfapi/render/cpdf_docrenderdata_unittest.cpp b/core/fpdfapi/render/cpdf_docrenderdata_unittest.cpp
index cd38bcc..3859091 100644
--- a/core/fpdfapi/render/cpdf_docrenderdata_unittest.cpp
+++ b/core/fpdfapi/render/cpdf_docrenderdata_unittest.cpp
@@ -15,6 +15,7 @@
 #include "core/fxcrt/fx_memory_wrappers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/base/ptr_util.h"
+#include "third_party/base/stl_util.h"
 
 namespace {
 
@@ -88,7 +89,7 @@
   func_dict->SetNewFor<CPDF_Number>("BitsPerSample", 8);
 
   static const char content[] = "1234";
-  size_t len = FX_ArraySize(content);
+  size_t len = pdfium::size(content);
   std::unique_ptr<uint8_t, FxFreeDeleter> buf(FX_AllocUninit(uint8_t, len));
   memcpy(buf.get(), content, len);
   return pdfium::MakeRetain<CPDF_Stream>(std::move(buf), len,
@@ -130,7 +131,7 @@
   range_array->AppendNew<CPDF_Number>(1);
 
   static const char content[] = "{ 360 mul sin 2 div }";
-  size_t len = FX_ArraySize(content);
+  size_t len = pdfium::size(content);
   std::unique_ptr<uint8_t, FxFreeDeleter> buf(FX_AllocUninit(uint8_t, len));
   memcpy(buf.get(), content, len);
   return pdfium::MakeRetain<CPDF_Stream>(std::move(buf), len,
@@ -150,7 +151,7 @@
   range_array->AppendNew<CPDF_Number>(1);
 
   static const char content[] = "garbage";
-  size_t len = FX_ArraySize(content);
+  size_t len = pdfium::size(content);
   std::unique_ptr<uint8_t, FxFreeDeleter> buf(FX_AllocUninit(uint8_t, len));
   memcpy(buf.get(), content, len);
   return pdfium::MakeRetain<CPDF_Stream>(std::move(buf), len,
@@ -178,11 +179,11 @@
   auto r_samples = func->GetSamplesR();
   auto g_samples = func->GetSamplesG();
   auto b_samples = func->GetSamplesB();
-  ASSERT_EQ(FX_ArraySize(kExpectedType2FunctionSamples), r_samples.size());
-  ASSERT_EQ(FX_ArraySize(kExpectedType2FunctionSamples), g_samples.size());
-  ASSERT_EQ(FX_ArraySize(kExpectedType2FunctionSamples), b_samples.size());
+  ASSERT_EQ(pdfium::size(kExpectedType2FunctionSamples), r_samples.size());
+  ASSERT_EQ(pdfium::size(kExpectedType2FunctionSamples), g_samples.size());
+  ASSERT_EQ(pdfium::size(kExpectedType2FunctionSamples), b_samples.size());
 
-  for (size_t i = 0; i < FX_ArraySize(kExpectedType2FunctionSamples); ++i) {
+  for (size_t i = 0; i < pdfium::size(kExpectedType2FunctionSamples); ++i) {
     EXPECT_EQ(kExpectedType2FunctionSamples[i], r_samples[i]);
     EXPECT_EQ(kExpectedType2FunctionSamples[i], g_samples[i]);
     EXPECT_EQ(kExpectedType2FunctionSamples[i], b_samples[i]);
@@ -214,11 +215,11 @@
   auto r_samples = func->GetSamplesR();
   auto g_samples = func->GetSamplesG();
   auto b_samples = func->GetSamplesB();
-  ASSERT_EQ(FX_ArraySize(kExpectedType0FunctionSamples), r_samples.size());
-  ASSERT_EQ(FX_ArraySize(kExpectedType2FunctionSamples), g_samples.size());
-  ASSERT_EQ(FX_ArraySize(kExpectedType4FunctionSamples), b_samples.size());
+  ASSERT_EQ(pdfium::size(kExpectedType0FunctionSamples), r_samples.size());
+  ASSERT_EQ(pdfium::size(kExpectedType2FunctionSamples), g_samples.size());
+  ASSERT_EQ(pdfium::size(kExpectedType4FunctionSamples), b_samples.size());
 
-  for (size_t i = 0; i < FX_ArraySize(kExpectedType2FunctionSamples); ++i) {
+  for (size_t i = 0; i < pdfium::size(kExpectedType2FunctionSamples); ++i) {
     EXPECT_EQ(kExpectedType0FunctionSamples[i], r_samples[i]);
     EXPECT_EQ(kExpectedType2FunctionSamples[i], g_samples[i]);
     EXPECT_EQ(kExpectedType4FunctionSamples[i], b_samples[i]);
diff --git a/core/fxge/cfx_fontmapper.h b/core/fxge/cfx_fontmapper.h
index d063adf..67be9da 100644
--- a/core/fxge/cfx_fontmapper.h
+++ b/core/fxge/cfx_fontmapper.h
@@ -22,7 +22,7 @@
 
 class CFX_FontMapper {
  public:
-  enum StandardFont {
+  enum StandardFont : uint8_t {
     kCourier = 0,
     kCourierBold,
     kCourierBoldOblique,