Revert of SkSL performance improvements

src/sksl/ir/SkSLTypeReference.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
  
 #ifndef SKSL_TYPEREFERENCE
 #define SKSL_TYPEREFERENCE
 
 #include "SkSLExpression.h"
 
 namespace SkSL {
 
 /**
  * Represents an identifier referring to a type. This is an intermediate value: TypeReferences are 
  * always eventually replaced by Constructors in valid programs.
  */
 struct TypeReference : public Expression {
-    TypeReference(Position position, const Type& type)
-    : INHERITED(position, kTypeReference_Kind, *kInvalid_Type)
-    , fValue(type) {}
+    TypeReference(Position position, std::shared_ptr<Type> type)
+    : INHERITED(position, kTypeReference_Kind, kInvalid_Type)
+    , fValue(std::move(type)) {}
 
     std::string description() const override {
         ASSERT(false);
         return "<type>";
     }
 
-    const Type& fValue;
+    const std::shared_ptr<Type> fValue;
 
     typedef Expression INHERITED;
 };
 
 } // namespace
 
 #endif