SkPDF: flip saveLayer rightside up

src/pdf/SkPDFFormXObject.cpp

Index: src/pdf/SkPDFFormXObject.cpp
diff --git a/src/pdf/SkPDFFormXObject.cpp b/src/pdf/SkPDFFormXObject.cpp
index 1ab391c3460a78f27bba186af11a2f3529e07382..e6445f517ae56f0f2fff4b75b4f684640a69f3bd 100644
--- a/src/pdf/SkPDFFormXObject.cpp
+++ b/src/pdf/SkPDFFormXObject.cpp
@@ -7,14 +7,20 @@
 
 
 #include "SkPDFFormXObject.h"
+#include "SkPDFUtils.h"
 
 sk_sp<SkPDFObject> SkPDFMakeFormXObject(std::unique_ptr<SkStreamAsset> content,
                                         sk_sp<SkPDFArray> mediaBox,
                                         sk_sp<SkPDFDict> resourceDict,
+                                        const SkMatrix& inverseTransform,
                                         const char* colorSpace) {
     auto form = sk_make_sp<SkPDFStream>(std::move(content));
     form->insertName("Type", "XObject");
     form->insertName("Subtype", "Form");
+    if (!inverseTransform.isIdentity()) {
+        form->insertObject("Matrix",
+                           SkPDFUtils::MatrixToArray(inverseTransform));
+    }
     form->insertObject("Resources", std::move(resourceDict));
     form->insertObject("BBox", std::move(mediaBox));