Fix incorrect current transformation matrix when saving PDFs

CPDF_PageContentGenerator has been incorrectly writing out the inverse
of the current transformation matrix when saving PDFs, instead of the
CTM. The reason this worked for many test cases is because they tested
PDFs where the inverted CTM is equal to the CTM. With new test cases
where the inverted CTM is not equal to the CTM, making this correction
makes them render correctly.

Bug: pdfium:2132
Change-Id: Idb0a7951d68dfdfaa30f9a41479b6941c341b4aa
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/117053
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Thomas Sepez <tsepez@google.com>

core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp

diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
index 60a6ea9..c2f83dc 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
@@ -183,7 +183,7 @@
     buf << "q\n";
     const CFX_Matrix& ctm = m_pObjHolder->GetLastCTM();
     if (!ctm.IsIdentity()) {
-      WriteMatrix(buf, ctm.GetInverse()) << " cm\n";
+      WriteMatrix(buf, ctm) << " cm\n";
     }
 
     ProcessDefaultGraphics(&buf);

fpdfsdk/fpdf_edit_embeddertest.cpp

diff --git a/fpdfsdk/fpdf_edit_embeddertest.cpp b/fpdfsdk/fpdf_edit_embeddertest.cpp
index 39c205c..22ce975 100644
--- a/fpdfsdk/fpdf_edit_embeddertest.cpp
+++ b/fpdfsdk/fpdf_edit_embeddertest.cpp
@@ -5267,24 +5267,7 @@
 
   UnloadPage(page);
 
-  // TODO(crbug.com/pdfium/2132): This should use HelloWorldChecksum().
-  const char* const kWrongChecksum = []() {
-    if (CFX_DefaultRenderDevice::UseSkiaRenderer()) {
-#if BUILDFLAG(IS_WIN)
-      return "0b5370959c7731c846a35066f0463aee";
-#elif BUILDFLAG(IS_MAC)
-      return "8715c645f7dccfb23e25a32da32ef6af";
-#else
-      return "b4a1a4a73668c5dd4b769db86334943b";
-#endif
-    }
-#if BUILDFLAG(IS_MAC)
-    return "6cb1bfe4f8bef5547eab41cdfad79d59";
-#else
-    return "0e6dd5f1332bb4c4b0cd3aa6a0b89943";
-#endif
-  }();
-  VerifySavedDocument(kExpectedWidth, kExpectedHeight, kWrongChecksum);
+  VerifySavedDocument(kExpectedWidth, kExpectedHeight, HelloWorldChecksum());
 }
 
 class FPDFEditMoveEmbedderTest : public EmbedderTest {

fpdfsdk/fpdf_editpath_embeddertest.cpp

diff --git a/fpdfsdk/fpdf_editpath_embeddertest.cpp b/fpdfsdk/fpdf_editpath_embeddertest.cpp
index 91103aa..9a9fe63 100644
--- a/fpdfsdk/fpdf_editpath_embeddertest.cpp
+++ b/fpdfsdk/fpdf_editpath_embeddertest.cpp
@@ -186,12 +186,5 @@
 
   UnloadPage(page);
 
-  // TODO(crbug.com/pdfium/2132): This should use RectanglesChecksum().
-  const char* const kWrongChecksum = []() {
-    if (CFX_DefaultRenderDevice::UseSkiaRenderer()) {
-      return "f7c69f8d0bb92541d48dbbbba003396d";
-    }
-    return "37a215071985bd88079fedb56b001685";
-  }();
-  VerifySavedDocument(kExpectedWidth, kExpectedHeight, kWrongChecksum);
+  VerifySavedDocument(kExpectedWidth, kExpectedHeight, RectanglesChecksum());
 }