Implement clone for 4 additional GrFragmentProcessors.

GrConfigConversionEffect
GrConstColorProcessor
GrConvexPolyEffect
AARectEffect

Change-Id: I3b103ed045db0825fc193ee7d6e61c8fe8e5c634
Reviewed-on: https://skia-review.googlesource.com/26842
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/effects/GrConfigConversionEffect.h b/src/gpu/effects/GrConfigConversionEffect.h
index f6bb7b1..fe8f50b 100644
--- a/src/gpu/effects/GrConfigConversionEffect.h
+++ b/src/gpu/effects/GrConfigConversionEffect.h
@@ -33,6 +33,8 @@
 
     const char* name() const override { return "Config Conversion"; }
 
+    sk_sp<GrFragmentProcessor> clone() const override;
+
     PMConversion  pmConversion() const { return fPMConversion; }
 
     // This function determines whether it is possible to choose PM->UPM and UPM->PM conversions