CppunitTest_vcl_pdfexport: fix use after free

Just do the minimal fixing, a follow-up commit should clean up the
copy&paste coding that happened here in previous commits.

Change-Id: I44306e2fee57d55997414e62120c7e5037f306fb
Reviewed-on: https://gerrit.libreoffice.org/60757Tested-by: Michael Stahl <Michael.Stahl@cib.de>
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>

vcl/qa/cppunit/pdfexport/pdfexport.cxx

@@ -38,6 +38,8 @@ class PdfExportTest : public test::BootstrapFixture, public unotest::MacrosTest
     uno::Reference<lang::XComponent> mxComponent;
     FPDF_PAGE mpPdfPage = nullptr;
     FPDF_DOCUMENT mpPdfDocument = nullptr;
+    /// Underlying memory of mpPdfDocument.
+    SvMemoryStream maPdfMemory;
     utl::TempFile maTempFile;
     SvMemoryStream maMemory;
     // Export the document as PDF, then parse it with PDFium.
@@ -287,9 +289,8 @@ void PdfExportTest::testTdf105461()
 
     // Parse the export result with pdfium.
     SvFileStream aFile(maTempFile.GetURL(), StreamMode::READ);
-    SvMemoryStream aMemory;
-    aMemory.WriteStream(aFile);
-    mpPdfDocument = FPDF_LoadMemDocument(aMemory.GetData(), aMemory.GetSize(), /*password=*/nullptr);
+    maPdfMemory.WriteStream(aFile);
+    mpPdfDocument = FPDF_LoadMemDocument(maPdfMemory.GetData(), maPdfMemory.GetSize(), /*password=*/nullptr);
     CPPUNIT_ASSERT(mpPdfDocument);
 
     // The document has one page.
@@ -339,9 +340,8 @@ void PdfExportTest::testTdf107868()
 
     // Parse the export result with pdfium.
     SvFileStream aFile(maTempFile.GetURL(), StreamMode::READ);
-    SvMemoryStream aMemory;
-    aMemory.WriteStream(aFile);
-    mpPdfDocument = FPDF_LoadMemDocument(aMemory.GetData(), aMemory.GetSize(), /*password=*/nullptr);
+    maPdfMemory.WriteStream(aFile);
+    mpPdfDocument = FPDF_LoadMemDocument(maPdfMemory.GetData(), maPdfMemory.GetSize(), /*password=*/nullptr);
     if (!mpPdfDocument)
         // Printing to PDF failed in a non-interesting way, e.g. CUPS is not
         // running, there is no printer defined, etc.
@@ -769,9 +769,8 @@ void PdfExportTest::testTdf108963()
 
     // Parse the export result with pdfium.
     SvFileStream aFile(maTempFile.GetURL(), StreamMode::READ);
-    SvMemoryStream aMemory;
-    aMemory.WriteStream(aFile);
-    mpPdfDocument = FPDF_LoadMemDocument(aMemory.GetData(), aMemory.GetSize(), /*password=*/nullptr);
+    maPdfMemory.WriteStream(aFile);
+    mpPdfDocument = FPDF_LoadMemDocument(maPdfMemory.GetData(), maPdfMemory.GetSize(), /*password=*/nullptr);
     CPPUNIT_ASSERT(mpPdfDocument);
 
     // The document has one page.
@@ -973,9 +972,8 @@ void PdfExportTest::testTdf115117_1a()
 
     // Parse the export result with pdfium.
     SvFileStream aFile(maTempFile.GetURL(), StreamMode::READ);
-    SvMemoryStream aMemory;
-    aMemory.WriteStream(aFile);
-    mpPdfDocument = FPDF_LoadMemDocument(aMemory.GetData(), aMemory.GetSize(), /*password=*/nullptr);
+    maPdfMemory.WriteStream(aFile);
+    mpPdfDocument = FPDF_LoadMemDocument(maPdfMemory.GetData(), maPdfMemory.GetSize(), /*password=*/nullptr);
     CPPUNIT_ASSERT(mpPdfDocument);
 
     // The document has one page.
@@ -1016,9 +1014,8 @@ void PdfExportTest::testTdf115117_2a()
 
     // Parse the export result with pdfium.
     SvFileStream aFile(maTempFile.GetURL(), StreamMode::READ);
-    SvMemoryStream aMemory;
-    aMemory.WriteStream(aFile);
-    mpPdfDocument = FPDF_LoadMemDocument(aMemory.GetData(), aMemory.GetSize(), /*password=*/nullptr);
+    maPdfMemory.WriteStream(aFile);
+    mpPdfDocument = FPDF_LoadMemDocument(maPdfMemory.GetData(), maPdfMemory.GetSize(), /*password=*/nullptr);
     CPPUNIT_ASSERT(mpPdfDocument);
 
     // The document has one page.
@@ -1327,10 +1324,9 @@ void PdfExportTest::testTdf105954()
 
     // Parse the export result with pdfium.
     SvFileStream aFile(maTempFile.GetURL(), StreamMode::READ);
-    SvMemoryStream aMemory;
-    aMemory.WriteStream(aFile);
+    maPdfMemory.WriteStream(aFile);
     mpPdfDocument
-        = FPDF_LoadMemDocument(aMemory.GetData(), aMemory.GetSize(), /*password=*/nullptr);
+        = FPDF_LoadMemDocument(maPdfMemory.GetData(), maPdfMemory.GetSize(), /*password=*/nullptr);
     CPPUNIT_ASSERT(mpPdfDocument);
 
     // The document has one page.