[xfa] Verify we can get a font manager before setting up XFA

When setting up an XFA document we need to create a font manager. That
font manager requires the CFGAS_FontMgr to be provided, and ASSERTs to
that fact. It's possible for the CFGAS_FontMgr to be nullptr if we fail
to enumerate the system fonts.

This CL verifys we can get the needed manager and fails out of the XFA
OpenDoc method if we have no font manager.

Bug: chromium:835693
Change-Id: I806f265075dcc355e0a7aeb4b3ae8eb950aa5eee
Reviewed-on: https://pdfium-review.googlesource.com/32052
Commit-Queue: dsinclair <dsinclair@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/xfa/fxfa/cxfa_ffdoc.cpp b/xfa/fxfa/cxfa_ffdoc.cpp
index 12e2a7b5f6..bc4a939078 100644
--- a/xfa/fxfa/cxfa_ffdoc.cpp
+++ b/xfa/fxfa/cxfa_ffdoc.cpp
@@ -116,11 +116,13 @@ bool CXFA_FFDoc::OpenDoc(CPDF_Document* pPDFDoc) {
     return false;
   }
 
+  CFGAS_FontMgr* mgr = GetApp()->GetFDEFontMgr();
+  if (!mgr)
+    return false;
+
   // At this point we've got an XFA document and we want to always return
   // true to signify the load succeeded.
-
-  m_pPDFFontMgr = pdfium::MakeUnique<CFGAS_PDFFontMgr>(
-      GetPDFDoc(), GetApp()->GetFDEFontMgr());
+  m_pPDFFontMgr = pdfium::MakeUnique<CFGAS_PDFFontMgr>(GetPDFDoc(), mgr);
 
   m_FormType = FormType::kXFAForeground;
   CXFA_Node* pConfig = ToNode(m_pDocument->GetXFAObject(XFA_HASHCODE_Config));