Avoid regenerating appearance stream when already present.

Since cpdfsdk_widget.cpp already generates it, we can expect that
FPDF_GenerateAP will not be called. That implementation does not
work with widgets with a shared field.

Bug: chromium:733528
Change-Id: Ia436b4e8bc87ca86b67a02cf7301ac2328339128
Reviewed-on: https://pdfium-review.googlesource.com/6752
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>

4 files changed, 73 insertions, 1 deletions

diff --git a/core/fpdfdoc/cpdf_annotlist.cpp b/core/fpdfdoc/cpdf_annotlist.cpp
index 1427c85616..1f94779c15 100644
--- a/core/fpdfdoc/cpdf_annotlist.cpp
+++ b/core/fpdfdoc/cpdf_annotlist.cpp
@@ -86,7 +86,7 @@ CPDF_AnnotList::CPDF_AnnotList(CPDF_Page* pPage)
     pAnnots->ConvertToIndirectObjectAt(i, m_pDocument);
     m_AnnotList.push_back(pdfium::MakeUnique<CPDF_Annot>(pDict, m_pDocument));
     if (bRegenerateAP && subtype == "Widget" &&
-        CPDF_InterForm::IsUpdateAPEnabled()) {
+        CPDF_InterForm::IsUpdateAPEnabled() && !pDict->GetDictFor("AP")) {
       FPDF_GenerateAP(m_pDocument, pDict);
     }
   }
diff --git a/testing/resources/pixel/bug_733528.in b/testing/resources/pixel/bug_733528.in
new file mode 100644
index 0000000000..3602c3f2b5
--- /dev/null
+++ b/testing/resources/pixel/bug_733528.in
@@ -0,0 +1,72 @@
+{{header}}
+{{object 1 0}} <<
+  /Type /Catalog
+  /Pages 2 0 R
+  /AcroForm <<
+    /Fields [ 4 0 R 9 0 R ]
+    /DR 5 0 R
+    /NeedAppearances true
+  >>
+>>
+endobj
+{{object 2 0}} <<
+  /Count 1
+  /Kids [ 3 0 R ]
+  /Type /Pages
+>>
+endobj
+{{object 3 0}} <<
+  /Type /Page
+  /Parent 2 0 R
+  /Resources 5 0 R
+  /MediaBox [ 0 0 300 200 ]
+  /Contents 8 0 R
+  /Annots [ 4 0 R 9 0 R ]
+>>
+endobj
+{{object 4 0}} <<
+  /Type /Annot
+  /FT /Tx
+  /T (SharedField)
+  /DA (0 0 0 rg /F1 12 Tf)
+  /Rect [ 100 100 200 130 ]
+  /Subtype /Widget
+  /V (Hello, world)
+>>
+endobj
+{{object 5 0}} <<
+  /Font 6 0 R
+>>
+endobj
+{{object 6 0}} <<
+  /F1 7 0 R
+>>
+endobj
+{{object 7 0}} <<
+  /Type /Font
+  /Subtype /Type1
+  /BaseFont /Helvetica
+>>
+endobj
+{{object 8 0}} <<
+>>
+stream
+endstream
+endobj
+{{object 9 0}} <<
+  /Type /Annot
+  /FT /Tx
+  /T (SharedField)
+  /DA (0 0 0 rg /F1 12 Tf)
+  /Rect [ 100 40 200 70 ]
+  /Subtype /Widget
+  /V ()
+>>
+endobj
+{{xref}}
+trailer <<
+  /Root 1 0 R
+  /Size 10
+>>
+{{startxref}}
+%%EOF
diff --git a/testing/resources/pixel/bug_733528_expected.pdf.0.png b/testing/resources/pixel/bug_733528_expected.pdf.0.png
new file mode 100644
index 0000000000..cdd39c1434
--- /dev/null
+++ b/testing/resources/pixel/bug_733528_expected.pdf.0.png
diff --git a/testing/resources/pixel/bug_733528_expected_mac.pdf.0.png b/testing/resources/pixel/bug_733528_expected_mac.pdf.0.png
new file mode 100644
index 0000000000..f7c8302b1e
--- /dev/null
+++ b/testing/resources/pixel/bug_733528_expected_mac.pdf.0.png