Remove CFX_{Byte,Wide}String::ConvertFrom().

core/src/fpdfdoc/doc_basic_unittest.cpp

Index: core/src/fpdfdoc/doc_basic_unittest.cpp
diff --git a/core/src/fpdfdoc/doc_basic_unittest.cpp b/core/src/fpdfdoc/doc_basic_unittest.cpp
index ecc603aa9ed762330d870d0910d26763e1be032f..c2fd3ff2b2cc1346f290f99490691522db5bba45 100644
--- a/core/src/fpdfdoc/doc_basic_unittest.cpp
+++ b/core/src/fpdfdoc/doc_basic_unittest.cpp
@@ -145,8 +145,7 @@ TEST(doc_basic_filespec, SetFileName) {
   CPDF_FileSpec file_spec1(str_obj.get());
   file_spec1.SetFileName(test_data.input);
   // Check internal object value.
-  CFX_ByteString str;
-  str.ConvertFrom(test_data.expected);
+  CFX_ByteString str = CFX_ByteString::FromUnicode(test_data.expected);
   EXPECT_TRUE(str == str_obj->GetString());
   // Check we can get the file name back.
   CFX_WideString file_name;