SkPDF: PDFStream has-a not is-a PDFDict

src/pdf/SkPDFGraphicState.cpp

Index: src/pdf/SkPDFGraphicState.cpp
diff --git a/src/pdf/SkPDFGraphicState.cpp b/src/pdf/SkPDFGraphicState.cpp
index 3edf7458da7954c55ad695016ee9a72749af218b..7b793e6ea8df4fbf3c2861e2174814ccc118dd91 100644
--- a/src/pdf/SkPDFGraphicState.cpp
+++ b/src/pdf/SkPDFGraphicState.cpp
@@ -137,9 +137,9 @@ sk_sp<SkPDFStream> SkPDFGraphicState::MakeInvertFunction() {
     // Do not copy the trailing '\0' into the SkData.
     auto invertFunction = sk_make_sp<SkPDFStream>(
             SkData::MakeWithoutCopy(psInvert, strlen(psInvert)));
-    invertFunction->insertInt("FunctionType", 4);
-    invertFunction->insertObject("Domain", domainAndRange);
-    invertFunction->insertObject("Range", std::move(domainAndRange));
+    invertFunction->dict()->insertInt("FunctionType", 4);
+    invertFunction->dict()->insertObject("Domain", domainAndRange);
+    invertFunction->dict()->insertObject("Range", std::move(domainAndRange));
     return invertFunction;
 }