SkSL performance improvements

src/sksl/ir/SkSLFunctionDefinition.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_FUNCTIONDEFINITION
 #define SKSL_FUNCTIONDEFINITION
 
 #include "SkSLBlock.h"
 #include "SkSLFunctionDeclaration.h"
 #include "SkSLProgramElement.h"
 
 namespace SkSL {
 
 /**
  * A function definition (a declaration plus an associated block of code).
  */
 struct FunctionDefinition : public ProgramElement {
-    FunctionDefinition(Position position, std::shared_ptr<FunctionDeclaration> declaration,
+    FunctionDefinition(Position position, const FunctionDeclaration& declaration, 
                        std::unique_ptr<Block> body)
     : INHERITED(position, kFunction_Kind)
-    , fDeclaration(std::move(declaration))
+    , fDeclaration(declaration)
     , fBody(std::move(body)) {}
 
     std::string description() const override {
-        return fDeclaration->description() + " " + fBody->description();
+        return fDeclaration.description() + " " + fBody->description();
     }
 
-    const std::shared_ptr<FunctionDeclaration> fDeclaration;
+    const FunctionDeclaration& fDeclaration;
     const std::unique_ptr<Block> fBody;
 
     typedef ProgramElement INHERITED;
 };
 
 } // namespace
 
 #endif