Revert of Remove SK_SUPPORT_LEGACY_DEEPFLATTENING.

src/effects/SkPixelXorXfermode.cpp

Index: src/effects/SkPixelXorXfermode.cpp
diff --git a/src/effects/SkPixelXorXfermode.cpp b/src/effects/SkPixelXorXfermode.cpp
index 2a6ac47aac4fb8e34a948ed2c8debeefd9cf9947..68b5306a5262cf1e6872dcecb9bc15ffd5ea69fa 100644
--- a/src/effects/SkPixelXorXfermode.cpp
+++ b/src/effects/SkPixelXorXfermode.cpp
@@ -25,6 +25,12 @@
     wb.writeColor(fOpColor);
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
+SkPixelXorXfermode::SkPixelXorXfermode(SkReadBuffer& rb) : INHERITED(rb) {
+    fOpColor = rb.readColor();
+}
+#endif
+
 SkFlattenable* SkPixelXorXfermode::CreateProc(SkReadBuffer& buffer) {
     return Create(buffer.readColor());
 }