use Make instead of Create to return a shared shader

src/core/SkPaint.cpp

Index: src/core/SkPaint.cpp
diff --git a/src/core/SkPaint.cpp b/src/core/SkPaint.cpp
index 3d768074cad262bc64fe4c34569f8bdcd67666a9..678b1a1102558355c430f851a5f355290367cb0a 100644
--- a/src/core/SkPaint.cpp
+++ b/src/core/SkPaint.cpp
@@ -1929,7 +1929,7 @@ void SkPaint::unflatten(SkReadBuffer& buffer) {
 
     if (flatFlags & kHasEffects_FlatFlag) {
         SkSafeUnref(this->setPathEffect(buffer.readPathEffect()));
-        SkSafeUnref(this->setShader(buffer.readShader()));
+        this->setShader(buffer.readShader());
         SkSafeUnref(this->setXfermode(buffer.readXfermode()));
         SkSafeUnref(this->setMaskFilter(buffer.readMaskFilter()));
         SkSafeUnref(this->setColorFilter(buffer.readColorFilter()));