Make CFX_CodecMemory XFA-only

It is only used by XFA-specific decoders.

Change-Id: I6129755f700445ddb77ebc040486b15f64b70f36
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/119412
Reviewed-by: Thomas Sepez <tsepez@google.com>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxcodec/BUILD.gn b/core/fxcodec/BUILD.gn
index 46bdb06..df96eb1 100644
--- a/core/fxcodec/BUILD.gn
+++ b/core/fxcodec/BUILD.gn
@@ -9,8 +9,6 @@
   sources = [
     "basic/basicmodule.cpp",
     "basic/basicmodule.h",
-    "cfx_codec_memory.cpp",
-    "cfx_codec_memory.h",
     "data_and_bytes_consumed.cpp",
     "data_and_bytes_consumed.h",
     "fax/faxmodule.cpp",
@@ -85,6 +83,8 @@
   ]
   if (pdf_enable_xfa) {
     sources += [
+      "cfx_codec_memory.cpp",
+      "cfx_codec_memory.h",
       "jpeg/jpeg_progressive_decoder.cpp",
       "jpeg/jpeg_progressive_decoder.h",
       "progressive_decoder.cpp",