Remove unused code in FontCacheSkia (flutter#2805)

sky/engine/platform/fonts/skia/FontCacheSkia.cpp

@@ -49,24 +49,6 @@
 #include "third_party/skia/include/ports/SkFontConfigInterface.h"
 #endif
 
-#if !OS(WIN) && !OS(ANDROID) && !OS(IOS) && !OS(MACOSX)
-// TODO(bungeman) remove this temporary code ASAP.
-// This namespace exists to ease transition of SkTypeface from using SkStream to SkStreamAsset.
-namespace tmp {
-// Like std::declval but only returns lvalue references, ok since it isn't used on rvalue references.
-template<typename T> T& declvall();
-// The return type of SkFontConfigInterface::openStream(const SkFontConfigInterface::FontIdentity&).
-using StreamType = decltype(tmp::declvall<SkFontConfigInterface>().openStream(tmp::declvall<const SkFontConfigInterface::FontIdentity&>()));
-}
-static tmp::StreamType streamForFontconfigInterfaceId(int fontconfigInterfaceId)
-{
-    SkAutoTUnref<SkFontConfigInterface> fci(SkFontConfigInterface::RefGlobal());
-    SkFontConfigInterface::FontIdentity fontIdentity;
-    fontIdentity.fID = fontconfigInterfaceId;
-    return fci->openStream(fontIdentity);
-}
-#endif
-
 namespace blink {
 
 static int toSkiaWeight(FontWeight weight)