use Make instead of Create to return a shared shader

src/core/SkLocalMatrixShader.cpp

Index: src/core/SkLocalMatrixShader.cpp
diff --git a/src/core/SkLocalMatrixShader.cpp b/src/core/SkLocalMatrixShader.cpp
index 336f1c49cfece6907224bf8be973f93e4ffed459..42b378d61a69d033fd1090af18239d1587f7e5f2 100644
--- a/src/core/SkLocalMatrixShader.cpp
+++ b/src/core/SkLocalMatrixShader.cpp
@@ -10,7 +10,7 @@
 SkFlattenable* SkLocalMatrixShader::CreateProc(SkReadBuffer& buffer) {
     SkMatrix lm;
     buffer.readMatrix(&lm);
-    SkAutoTUnref<SkShader> baseShader(buffer.readShader());
+    auto baseShader(buffer.readShader());
     if (!baseShader) {
         return nullptr;
     }