Allow gradient optimization with perspective

src/effects/gradients/SkGradientShaderPriv.h

Index: src/effects/gradients/SkGradientShaderPriv.h
diff --git a/src/effects/gradients/SkGradientShaderPriv.h b/src/effects/gradients/SkGradientShaderPriv.h
index 8f96bbffe9ef3be28919f6a22f461ee795effc4c..f45b7773ead56ea8dba8d3fcaa165310ba5db528 100644
--- a/src/effects/gradients/SkGradientShaderPriv.h
+++ b/src/effects/gradients/SkGradientShaderPriv.h
@@ -288,6 +288,8 @@ protected:
 
     virtual bool onIsEqual(const GrEffect& effect) const SK_OVERRIDE;
 
+    const GrCoordTransform& getCoordTransform() const { return fCoordTransform; }
+
 private:
     static const GrCoordSet kCoordSet = kLocal_GrCoordSet;