CFGAS_PDFFontMgr need not be Observable.

Since no code observes it in the first place.

Change-Id: Id2424ff02022373bad3ea7fb1e36e2793e0f4aa4
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/92730
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

xfa/fgas/font/cfgas_pdffontmgr.h

diff --git a/xfa/fgas/font/cfgas_pdffontmgr.h b/xfa/fgas/font/cfgas_pdffontmgr.h
index 3bf9324..5d69ac0 100644
--- a/xfa/fgas/font/cfgas_pdffontmgr.h
+++ b/xfa/fgas/font/cfgas_pdffontmgr.h
@@ -10,7 +10,6 @@
 #include <map>
 
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/observed_ptr.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
 #include "xfa/fgas/font/cfgas_fontmgr.h"
@@ -18,7 +17,7 @@
 class CFGAS_GEFont;
 class CPDF_Document;
 
-class CFGAS_PDFFontMgr final : public Observable {
+class CFGAS_PDFFontMgr final {
  public:
   explicit CFGAS_PDFFontMgr(const CPDF_Document* pDoc);
   ~CFGAS_PDFFontMgr();