SkSL performance improvements

src/sksl/ir/SkSLVarDeclaration.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_VARDECLARATION
 #define SKSL_VARDECLARATION
 
 #include "SkSLExpression.h"
 #include "SkSLStatement.h"
 #include "SkSLVariable.h"
 
 namespace SkSL {
 
 /**
  * A variable declaration, which may consist of multiple individual variables. For instance
  * 'int x, y = 1, z[4][2];' is a single VarDeclaration. This declaration would have a type of 'int', 
  * names ['x', 'y', 'z'], sizes of [[], [], [4, 2]], and values of [null, 1, null].
  */
 struct VarDeclaration : public ProgramElement {
-    VarDeclaration(Position position, std::vector<std::shared_ptr<Variable>> vars,
+    VarDeclaration(Position position, std::vector<const Variable*> vars,
                    std::vector<std::vector<std::unique_ptr<Expression>>> sizes,
                    std::vector<std::unique_ptr<Expression>> values)
     : INHERITED(position, kVar_Kind) 
     , fVars(std::move(vars))
     , fSizes(std::move(sizes))
     , fValues(std::move(values)) {}
 
     std::string description() const override {
         std::string result = fVars[0]->fModifiers.description();
-        std::shared_ptr<Type> baseType = fVars[0]->fType;
+        const Type* baseType = &fVars[0]->fType;
         while (baseType->kind() == Type::kArray_Kind) {
-            baseType = baseType->componentType();
+            baseType = &baseType->componentType();
         }
         result += baseType->description();
         std::string separator = " ";
         for (size_t i = 0; i < fVars.size(); i++) {
             result += separator;
             separator = ", ";
             result += fVars[i]->fName;
             for (size_t j = 0; j < fSizes[i].size(); j++) {
                 if (fSizes[i][j]) {
                     result += "[" + fSizes[i][j]->description() + "]";
                 } else {
                     result += "[]";
                 }
             }
             if (fValues[i]) {
                 result += " = " + fValues[i]->description();
             }
         }
         result += ";";
         return result;
     }
 
-    const std::vector<std::shared_ptr<Variable>> fVars;
+    const std::vector<const Variable*> fVars;
     const std::vector<std::vector<std::unique_ptr<Expression>>> fSizes;
     const std::vector<std::unique_ptr<Expression>> fValues;
 
     typedef ProgramElement INHERITED;
 };
 
 } // namespace
 
 #endif