Plumb context through for serialization.

Change-Id: I2a49f57aa7576604deeac898a7cceb36ae68d66f
diff --git a/rsSampler.h b/rsSampler.h
index dea4cb6..81220a8 100644
--- a/rsSampler.h
+++ b/rsSampler.h
@@ -61,7 +61,7 @@
     void bindToContext(SamplerState *, uint32_t slot);
     void unbindFromContext(SamplerState *);
 
-    virtual void serialize(OStream *stream) const;
+    virtual void serialize(Context *rsc, OStream *stream) const;
     virtual RsA3DClassID getClassId() const { return RS_A3D_CLASS_ID_SAMPLER; }
     static Sampler *createFromStream(Context *rsc, IStream *stream);