Switch font embedding to a compile-time flag, with a todo for runtime.

src/core/SkPictureData.cpp

Index: src/core/SkPictureData.cpp
diff --git a/src/core/SkPictureData.cpp b/src/core/SkPictureData.cpp
index 73cf2bf215837dbac845850bf5ade507891d983d..ddd074e9a49882d6d762c5063aec8476c1d07c5e 100644
--- a/src/core/SkPictureData.cpp
+++ b/src/core/SkPictureData.cpp
@@ -177,10 +177,10 @@ void SkPictureData::WriteTypefaces(SkWStream* stream, const SkRefCntSet& rec) {
     rec.copyToArray((SkRefCnt**)array);
 
     for (int i = 0; i < count; i++) {
-#ifdef SK_BUILD_FOR_UNIX
+#ifdef SK_PICTURE_FORCE_FONT_EMBEDDING
         array[i]->serializeForcingEmbedding(stream);
 #else
-        // FIXME: Macs and Windows don't draw pixel-perfect if we embed fonts in the SKP.
+        // TODO: if (embedFonts) { array[i]->serializeForcingEmbedding(stream) } else
         array[i]->serialize(stream);
 #endif
     }