SkPDF: flip saveLayer rightside up

src/pdf/SkPDFDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPDFDevice.h"
 #include "SkAnnotationKeys.h"
 #include "SkBitmapDevice.h"
@@ skipping 1570 matching lines @@
         SkPoint p = fInitialTransform.mapXY(dest.point.x(), dest.point.y());
         pdfDest->appendScalar(p.x());
         pdfDest->appendScalar(p.y());
         pdfDest->appendInt(0);  // Leave zoom unchanged
         SkString name(static_cast<const char*>(dest.nameData->data()));
         dict->insertObject(name, std::move(pdfDest));
     }
 }
 
 sk_sp<SkPDFObject> SkPDFDevice::makeFormXObjectFromDevice() {
+    SkMatrix inverseTransform = SkMatrix::I();
+    if (!this->initialTransform().isIdentity()) {
+        if (!this->initialTransform().invert(&inverseTransform)) {
+            SkDEBUGFAIL("Layer initial transform should be invertible.");
+            inverseTransform.reset();
+        }
+    }
     sk_sp<SkPDFObject> xobject =
         SkPDFMakeFormXObject(this->content(), this->copyMediaBox(),
-                             this->makeResourceDict(), nullptr);
+                             this->makeResourceDict(), inverseTransform, nullptr);
     // We always draw the form xobjects that we create back into the device, so
     // we simply preserve the font usage instead of pulling it out and merging
     // it back in later.
     this->cleanUp();  // Reset this device to have no content.
     this->init();
     return xobject;
 }
 
 void SkPDFDevice::drawFormXObjectWithMask(int xObjectIndex,
                                           SkPDFObject* mask,
@@ skipping 617 matching lines @@
 }
 
 sk_sp<SkSpecialImage> SkPDFDevice::makeSpecial(const SkImage* image) {
     return SkSpecialImage::MakeFromImage(SkIRect::MakeWH(image->width(), image->height()),
                                          image->makeNonTextureImage());
 }
 
 sk_sp<SkSpecialImage> SkPDFDevice::snapSpecial() {
     return nullptr;
 }