Make CFX_FolderFontInfo file-reading helpers static methods.

Doing so will allow CFX_AndroidFontInfo to re-use this code in
a subsequent CL. No functional change.

Change-Id: I3ed34ed91581bf46165e3dca215a88b7bc316191
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/149711
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

core/fxge/cfx_folderfontinfo.cpp

diff --git a/core/fxge/cfx_folderfontinfo.cpp b/core/fxge/cfx_folderfontinfo.cpp
index 8c4af5f..3660000 100644
--- a/core/fxge/cfx_folderfontinfo.cpp
+++ b/core/fxge/cfx_folderfontinfo.cpp
@@ -57,8 +57,12 @@
   }
 };
 
-bool FindFamilyNameMatch(ByteStringView family_name,
-                         const ByteString& installed_font_name) {
+}  // namespace
+
+// static
+bool CFX_FolderFontInfo::FindFamilyNameMatch(
+    ByteStringView family_name,
+    const ByteString& installed_font_name) {
   std::optional<size_t> result = installed_font_name.Find(family_name, 0);
   if (!result.has_value()) {
     return false;
@@ -77,7 +81,8 @@
   return true;
 }
 
-ByteString ReadStringFromFile(FILE* pFile, uint32_t size) {
+// static
+ByteString CFX_FolderFontInfo::ReadStringFromFile(FILE* pFile, uint32_t size) {
   ByteString result;
   {
     // Span's lifetime must end before ReleaseBuffer() below.
@@ -91,11 +96,12 @@
   return result;
 }
 
-ByteString LoadTableFromTT(FILE* pFile,
-                           const uint8_t* pTables,
-                           uint32_t nTables,
-                           uint32_t tag,
-                           FX_FILESIZE fileSize) {
+// static
+ByteString CFX_FolderFontInfo::LoadTableFromTT(FILE* pFile,
+                                               const uint8_t* pTables,
+                                               uint32_t nTables,
+                                               uint32_t tag,
+                                               FX_FILESIZE fileSize) {
   UNSAFE_TODO({
     for (uint32_t i = 0; i < nTables; i++) {
       // TODO(tsepez): use actual span.
@@ -115,8 +121,6 @@
   return ByteString();
 }
 
-}  // namespace
-
 CFX_FolderFontInfo::CFX_FolderFontInfo() = default;
 
 CFX_FolderFontInfo::~CFX_FolderFontInfo() = default;

core/fxge/cfx_folderfontinfo.h

diff --git a/core/fxge/cfx_folderfontinfo.h b/core/fxge/cfx_folderfontinfo.h
index 98831fa..e2d6371 100644
--- a/core/fxge/cfx_folderfontinfo.h
+++ b/core/fxge/cfx_folderfontinfo.h
@@ -19,6 +19,15 @@
 
 class CFX_FolderFontInfo : public SystemFontInfoIface {
  public:
+  static bool FindFamilyNameMatch(ByteStringView family_name,
+                                  const ByteString& installed_font_name);
+  static ByteString ReadStringFromFile(FILE* pFile, uint32_t size);
+  static ByteString LoadTableFromTT(FILE* pFile,
+                                    const uint8_t* pTables,
+                                    uint32_t nTables,
+                                    uint32_t tag,
+                                    FX_FILESIZE fileSize);
+
   CFX_FolderFontInfo();
   ~CFX_FolderFontInfo() override;