switch xfermodes over to sk_sp

gm/avoidxfermode.cpp

Index: gm/avoidxfermode.cpp
diff --git a/gm/avoidxfermode.cpp b/gm/avoidxfermode.cpp
index d224b4e2d05d56808b76e9e2d2e700e970215fea..8e8dc2855372343970abc426679e9f0f6019f77e 100644
--- a/gm/avoidxfermode.cpp
+++ b/gm/avoidxfermode.cpp
@@ -37,9 +37,7 @@ protected:
         // UL corner: replace white with black with a tight tolerance
         SkPaint p1;
         p1.setColor(SK_ColorBLACK);
-        p1.setXfermode(SkAvoidXfermode::Create(SK_ColorWHITE,
-                                               5,
-                                               SkAvoidXfermode::kTargetColor_Mode))->unref();
+        p1.setXfermode(SkAvoidXfermode::Make(SK_ColorWHITE, 5, SkAvoidXfermode::kTargetColor_Mode));
 
         canvas->drawRect(r, p1);
 
@@ -48,9 +46,8 @@ protected:
         // UR corner: draw black everywhere except white with a tight tolerance
         SkPaint p2;
         p2.setColor(SK_ColorBLACK);
-        p2.setXfermode(SkAvoidXfermode::Create(SK_ColorWHITE,
-                                               250,
-                                               SkAvoidXfermode::kAvoidColor_Mode))->unref();
+        p2.setXfermode(SkAvoidXfermode::Make(SK_ColorWHITE, 250,
+                                             SkAvoidXfermode::kAvoidColor_Mode));
 
         canvas->drawRect(r, p2);
 
@@ -59,9 +56,7 @@ protected:
         // LL corner: replace red with transparent blue with a loose tolerance
         SkPaint p3;
         p3.setColor(0x7F0000FF);
-        p3.setXfermode(SkAvoidXfermode::Create(SK_ColorRED,
-                                               250,
-                                               SkAvoidXfermode::kTargetColor_Mode))->unref();
+        p3.setXfermode(SkAvoidXfermode::Make(SK_ColorRED, 250, SkAvoidXfermode::kTargetColor_Mode));
 
         canvas->drawRect(r, p3);
 
@@ -70,9 +65,7 @@ protected:
         // LR corner: draw black everywhere except red with a loose tolerance
         SkPaint p4;
         p4.setColor(SK_ColorBLACK);
-        p4.setXfermode(SkAvoidXfermode::Create(SK_ColorRED,
-                                               5,
-                                               SkAvoidXfermode::kAvoidColor_Mode))->unref();
+        p4.setXfermode(SkAvoidXfermode::Make(SK_ColorRED, 5, SkAvoidXfermode::kAvoidColor_Mode));
 
         canvas->drawRect(r, p4);
     }