use Make instead of Create to return a shared shader

tools/sk_tool_utils.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef sk_tool_utils_DEFINED
 #define sk_tool_utils_DEFINED
 
@@ skipping 74 matching lines @@
     /**
      *  Call canvas->writePixels() by using the pixels from bitmap, but with an info that claims
      *  the pixels are colorType + alphaType
      */
     void write_pixels(SkCanvas*, const SkBitmap&, int x, int y, SkColorType, SkAlphaType);
 
     // private to sk_tool_utils
     SkTypeface* create_font(const char* name, SkTypeface::Style);
 
     /** Returns a newly created CheckerboardShader. */
-    SkShader* create_checkerboard_shader(SkColor c1, SkColor c2, int size);
+    sk_sp<SkShader> create_checkerboard_shader(SkColor c1, SkColor c2, int size);
 
     /** Draw a checkerboard pattern in the current canvas, restricted to
         the current clip, using SkXfermode::kSrc_Mode. */
     void draw_checkerboard(SkCanvas* canvas,
                            SkColor color1,
                            SkColor color2,
                            int checkSize);
 
     /** Make it easier to create a bitmap-based checkerboard */
     SkBitmap create_checkerboard_bitmap(int w, int h,
@@ skipping 110 matching lines @@
         int  fID;
         int  fOutputPos;
         bool fTempMark;
 
         SkTDArray<TopoTestNode*> fDependencies;
     };
 
 }  // namespace sk_tool_utils
 
 #endif  // sk_tool_utils_DEFINED