Use observed ptrs from CFGAS_GEFont back to its font mgrs.chromium/3106

CFGAS_GEFonts are ref counted, and its a good thing since they
are managed by at least three different font managers: 
CFGAS_FontMgr, CXFA_PDFFontMgr, and CXFA_FontMgr.  None of these
have a clear claim to ownership of the CFGAS_GEFont.

CFGAS_GEFont has back-pointers to two of these, CFGAS_FontMgr, and
CXFA_PDFFontMgr, and they could each outlive the other.  Thus the
font needs to watch for destruction of either of its managers, so
as to stop using it after its gone.

Bug: 724640
Change-Id: I907ec35e300e11e532e13545d51fb200ac86b4f9
Reviewed-on: https://pdfium-review.googlesource.com/5735
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/xfa/fgas/font/cfgas_fontmgr.h b/xfa/fgas/font/cfgas_fontmgr.h
index 1ef78a79a6..ca3cf1c710 100644
--- a/xfa/fgas/font/cfgas_fontmgr.h
+++ b/xfa/fgas/font/cfgas_fontmgr.h
@@ -14,12 +14,14 @@
 #include <vector>
 
 #include "core/fxcrt/cfx_crtfileaccess.h"
+#include "core/fxcrt/cfx_observable.h"
 #include "core/fxcrt/cfx_retain_ptr.h"
 #include "core/fxcrt/cfx_seekablestreamproxy.h"
 #include "core/fxcrt/fx_extension.h"
 #include "core/fxge/cfx_fontmapper.h"
 #include "core/fxge/fx_freetype.h"
 #include "core/fxge/ifx_systemfontinfo.h"
+#include "xfa/fxfa/cxfa_pdffontmgr.h"
 
 #define FX_FONTSTYLE_Normal 0x00
 #define FX_FONTSTYLE_FixedPitch 0x01
@@ -32,8 +34,6 @@
 #define FX_FONTSTYLE_ExactMatch 0x80000000
 
 class CFX_FontSourceEnum_File;
-class CXFA_PDFFontMgr;
-class CFGAS_FontMgr;
 class CFGAS_GEFont;
 
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
@@ -81,7 +81,7 @@ typedef void (*FX_LPEnumAllFonts)(std::deque<FX_FONTDESCRIPTOR>* fonts,
 
 FX_LPEnumAllFonts FX_GetDefFontEnumerator();
 
-class CFGAS_FontMgr {
+class CFGAS_FontMgr : public CFX_Observable<CFGAS_FontMgr> {
  public:
   static std::unique_ptr<CFGAS_FontMgr> Create(FX_LPEnumAllFonts pEnumerator);
 
@@ -180,7 +180,7 @@ class CFX_FontSourceEnum_File {
   std::vector<CFX_ByteString> m_FolderPaths;
 };
 
-class CFGAS_FontMgr {
+class CFGAS_FontMgr : public CFX_Observable<CFGAS_FontMgr> {
  public:
   static std::unique_ptr<CFGAS_FontMgr> Create(
       CFX_FontSourceEnum_File* pFontEnum);