Revert of Remove SK_SUPPORT_LEGACY_DEEPFLATTENING.

src/core/SkBlitter.cpp

Index: src/core/SkBlitter.cpp
diff --git a/src/core/SkBlitter.cpp b/src/core/SkBlitter.cpp
index ba260ad7166c103c409a5d3bf67c60cf0ba2146a..f4669d595995099e49217cb2aacefe03af056eab 100644
--- a/src/core/SkBlitter.cpp
+++ b/src/core/SkBlitter.cpp
@@ -714,6 +714,15 @@
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(Sk3DShader)
 
 protected:
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
+    Sk3DShader(SkReadBuffer& buffer) : INHERITED(buffer) {
+        fProxy = buffer.readShader();
+        // Leaving this here until we bump the picture version, though this
+        // shader should never be recorded.
+        buffer.readColor();
+    }
+#endif
+
     virtual void flatten(SkWriteBuffer& buffer) const SK_OVERRIDE {
         buffer.writeFlattenable(fProxy);
     }