Delete unused fNamedFactorySet from SkWriteBuffer

src/core/SkPictureFlat.cpp

Index: src/core/SkPictureFlat.cpp
diff --git a/src/core/SkPictureFlat.cpp b/src/core/SkPictureFlat.cpp
index 71f39ea0f9bc713fc6188857ebde8e53afebb443..792345885c13ba5fb84acb250c999737be1b0b90 100644
--- a/src/core/SkPictureFlat.cpp
+++ b/src/core/SkPictureFlat.cpp
@@ -63,13 +63,11 @@ SkFlatController::SkFlatController(uint32_t writeBufferFlags)
 : fBitmapHeap(nullptr)
 , fTypefaceSet(nullptr)
 , fTypefacePlayback(nullptr)
-, fFactorySet(nullptr)
 , fWriteBufferFlags(writeBufferFlags) {}
 
 SkFlatController::~SkFlatController() {
     SkSafeUnref(fBitmapHeap);
     SkSafeUnref(fTypefaceSet);
-    SkSafeUnref(fFactorySet);
 }
 
 void SkFlatController::setBitmapHeap(SkBitmapHeap* heap) {
@@ -83,8 +81,3 @@ void SkFlatController::setTypefaceSet(SkRefCntSet *set) {
 void SkFlatController::setTypefacePlayback(SkTypefacePlayback* playback) {
     fTypefacePlayback = playback;
 }
-
-SkNamedFactorySet* SkFlatController::setNamedFactorySet(SkNamedFactorySet* set) {
-    SkRefCnt_SafeAssign(fFactorySet, set);
-    return set;
-}