Test color correction in DM

src/core/SkColorSpace_Base.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkColorSpace_Base_DEFINED
 #define SkColorSpace_Base_DEFINED
 
@@ skipping 118 matching lines @@
     sk_sp<SkGammas>                   fGammas;
 
     friend class SkColorSpace;
     typedef SkColorSpace INHERITED;
 };
 
 static inline SkColorSpace_Base* as_CSB(SkColorSpace* colorSpace) {
     return static_cast<SkColorSpace_Base*>(colorSpace);
 }
 
+static inline SkColorSpace_Base* as_CSB(const sk_sp<SkColorSpace>& colorSpace) {
+    return static_cast<SkColorSpace_Base*>(colorSpace.get());
+}
+
 #endif