Remove GrEffect::CreateEffectRef and GrEffect::AutoEffectRef.

R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/371103003
diff --git a/src/effects/gradients/SkLinearGradient.cpp b/src/effects/gradients/SkLinearGradient.cpp
index 768623a..d518cc7 100644
--- a/src/effects/gradients/SkLinearGradient.cpp
+++ b/src/effects/gradients/SkLinearGradient.cpp
@@ -484,8 +484,7 @@
                                const SkLinearGradient& shader,
                                const SkMatrix& matrix,
                                SkShader::TileMode tm) {
-        AutoEffectUnref effect(SkNEW_ARGS(GrLinearGradient, (ctx, shader, matrix, tm)));
-        return CreateEffectRef(effect);
+        return SkNEW_ARGS(GrLinearGradient, (ctx, shader, matrix, tm));
     }
 
     virtual ~GrLinearGradient() { }