use Make instead of Create to return a shared shader

src/core/SkLocalMatrixShader.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLocalMatrixShader.h"
 
 SkFlattenable* SkLocalMatrixShader::CreateProc(SkReadBuffer& buffer) {
     SkMatrix lm;
     buffer.readMatrix(&lm);
-    SkAutoTUnref<SkShader> baseShader(buffer.readShader());
+    auto baseShader(buffer.readShader());
     if (!baseShader) {
         return nullptr;
     }
     return baseShader->newWithLocalMatrix(lm);
 }
 
 void SkLocalMatrixShader::flatten(SkWriteBuffer& buffer) const {
     buffer.writeMatrix(this->getLocalMatrix());
     buffer.writeFlattenable(fProxyShader.get());
 }
@@ skipping 34 matching lines @@
     SkMatrix otherLocalMatrix;
     SkAutoTUnref<SkShader> proxy(this->refAsALocalMatrixShader(&otherLocalMatrix));
     if (proxy) {
         otherLocalMatrix.preConcat(localMatrix);
         lm = &otherLocalMatrix;
         baseShader = proxy.get();
     }
 
     return new SkLocalMatrixShader(baseShader, *lm);
 }