Use CFX_FontMapper::MakeTag() in more places.

Prefer CFX_FontMapper::MakeTag(), which is constexpr, over cryptic tag
values or FT_MAKE_TAG().

Change-Id: Ic9d6123ecdc4f498d49eeb35088fc5572bfcf6c2
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/93350
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/core/fpdfapi/font/cpdf_cidfont.cpp b/core/fpdfapi/font/cpdf_cidfont.cpp
index d8988b7..46b595e 100644
--- a/core/fpdfapi/font/cpdf_cidfont.cpp
+++ b/core/fpdfapi/font/cpdf_cidfont.cpp
@@ -646,15 +646,16 @@
   if (m_pTTGSUBTable)
     return GetVerticalGlyph(index, pVertGlyph);
 
+  static constexpr uint32_t kGsubTag =
+      CFX_FontMapper::MakeTag('G', 'S', 'U', 'B');
   if (!m_Font.GetSubData()) {
     unsigned long length = 0;
-    int error = FT_Load_Sfnt_Table(face, FT_MAKE_TAG('G', 'S', 'U', 'B'), 0,
-                                   nullptr, &length);
+    int error = FT_Load_Sfnt_Table(face, kGsubTag, 0, nullptr, &length);
     if (!error)
       m_Font.SetSubData(FX_Alloc(uint8_t, length));
   }
-  int error = FT_Load_Sfnt_Table(face, FT_MAKE_TAG('G', 'S', 'U', 'B'), 0,
-                                 m_Font.GetSubData(), nullptr);
+  int error =
+      FT_Load_Sfnt_Table(face, kGsubTag, 0, m_Font.GetSubData(), nullptr);
   if (error || !m_Font.GetSubData())
     return index;
 
diff --git a/core/fxge/cfx_folderfontinfo.cpp b/core/fxge/cfx_folderfontinfo.cpp
index c40c13b..6a5aff0 100644
--- a/core/fxge/cfx_folderfontinfo.cpp
+++ b/core/fxge/cfx_folderfontinfo.cpp
@@ -244,8 +244,10 @@
   if (tables.IsEmpty())
     return;
 
+  static constexpr uint32_t kNameTag =
+      CFX_FontMapper::MakeTag('n', 'a', 'm', 'e');
   ByteString names =
-      LoadTableFromTT(pFile, tables.raw_str(), nTables, 0x6e616d65, filesize);
+      LoadTableFromTT(pFile, tables.raw_str(), nTables, kNameTag, filesize);
   if (names.IsEmpty())
     return;
 
@@ -262,8 +264,10 @@
 
   auto pInfo =
       std::make_unique<FontFaceInfo>(path, facename, tables, offset, filesize);
+  static constexpr uint32_t kOs2Tag =
+      CFX_FontMapper::MakeTag('O', 'S', '/', '2');
   ByteString os2 =
-      LoadTableFromTT(pFile, tables.raw_str(), nTables, 0x4f532f32, filesize);
+      LoadTableFromTT(pFile, tables.raw_str(), nTables, kOs2Tag, filesize);
   if (os2.GetLength() >= 86) {
     const uint8_t* p = os2.raw_str() + 78;
     uint32_t codepages = FXSYS_UINT32_GET_MSBFIRST(p);
diff --git a/core/fxge/cfx_fontmapper_unittest.cpp b/core/fxge/cfx_fontmapper_unittest.cpp
index 1d54526..274f865 100644
--- a/core/fxge/cfx_fontmapper_unittest.cpp
+++ b/core/fxge/cfx_fontmapper_unittest.cpp
@@ -39,4 +39,8 @@
             CFX_FontMapper::MakeTag('\xff', '\xff', '\xff', '\xff'));
   EXPECT_EQ(0xffffffffu,
             CFX_FontMapper::MakeTag(g_maybe_changes, '\xff', '\xff', '\xff'));
+  EXPECT_EQ(0x6e616d65u, CFX_FontMapper::MakeTag('n', 'a', 'm', 'e'));
+  EXPECT_EQ(0x4f532f32u, CFX_FontMapper::MakeTag('O', 'S', '/', '2'));
+  EXPECT_EQ(FT_MAKE_TAG('G', 'S', 'U', 'B'),
+            CFX_FontMapper::MakeTag('G', 'S', 'U', 'B'));
 }