Use Optional to determine if appearance stream as fontchromium/3388

This CL changes the CPDF_DefaultAppearance code to remove the HasFont
method and change GetFont to return an Optional. This forces all the
call sites to verify a font was returned correctly and removes the need
for the duplicate appearance stream parsing.

Bug: chromium:827430
Change-Id: If09e0a7d3f7dd63ad77b97a5a388127e4a02da61
Reviewed-on: https://pdfium-review.googlesource.com/29610
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/core/fpdfdoc/cpdf_formfield.cpp b/core/fpdfdoc/cpdf_formfield.cpp
index f3dcac2228..540e1c9ae0 100644
--- a/core/fpdfdoc/cpdf_formfield.cpp
+++ b/core/fpdfdoc/cpdf_formfield.cpp
@@ -915,11 +915,11 @@ void CPDF_FormField::LoadDA() {
     return;
 
   CPDF_DefaultAppearance appearance(DA);
-  if (!appearance.HasFont())
+  Optional<ByteString> font_name = appearance.GetFont(&m_FontSize);
+  if (!font_name)
     return;
 
-  ByteString font_name = appearance.GetFont(&m_FontSize);
-  CPDF_Dictionary* pFontDict = pFont->GetDictFor(font_name);
+  CPDF_Dictionary* pFontDict = pFont->GetDictFor(*font_name);
   if (!pFontDict)
     return;