Fix mac build under raw_ptr plugin

Use UNOWNED_PTR_EXCLUSION for mac-specific code.

Change-Id: Ibf4495d5af6ab469af065ebccb6f3daded94ef93
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/107291
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxge/cfx_font.h b/core/fxge/cfx_font.h
index bf94874..9197b22 100644
--- a/core/fxge/cfx_font.h
+++ b/core/fxge/cfx_font.h
@@ -18,6 +18,7 @@
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_memory_wrappers.h"
 #include "core/fxcrt/retain_ptr.h"
+#include "core/fxcrt/unowned_ptr_exclusion.h"
 #include "core/fxge/cfx_face.h"
 #include "core/fxge/freetype/fx_freetype.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
@@ -174,7 +175,7 @@
   bool m_bEmbedded = false;
   bool m_bVertical = false;
 #if BUILDFLAG(IS_APPLE)
-  void* m_pPlatformFont = nullptr;
+  UNOWNED_PTR_EXCLUSION void* m_pPlatformFont = nullptr;
 #endif
 };