added constant folding & branch elimination to skslc

src/sksl/SkSLIRGenerator.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_IRGENERATOR
 #define SKSL_IRGENERATOR
 
@@ skipping 146 matching lines @@
     std::unique_ptr<Expression> getCap(Position position, String name);
     std::unique_ptr<Expression> convertSuffixExpression(const ASTSuffixExpression& expression);
     std::unique_ptr<Expression> convertField(std::unique_ptr<Expression> base,
                                              const String& field);
     std::unique_ptr<Expression> convertSwizzle(std::unique_ptr<Expression> base,
                                                const String& fields);
     std::unique_ptr<Expression> convertTernaryExpression(const ASTTernaryExpression& expression);
     std::unique_ptr<Statement> convertVarDeclarationStatement(const ASTVarDeclarationStatement& s);
     std::unique_ptr<Statement> convertWhile(const ASTWhileStatement& w);
 
+    void fixRectSampling(std::vector<std::unique_ptr<Expression>>& arguments);
     void checkValid(const Expression& expr);
     void markWrittenTo(const Expression& expr, bool readWrite);
 
     const FunctionDeclaration* fCurrentFunction;
     const Program::Settings* fSettings;
     std::unordered_map<String, CapValue> fCapsMap;
     std::shared_ptr<SymbolTable> fSymbolTable;
     int fLoopLevel;
     int fSwitchLevel;
     ErrorReporter& fErrors;
 
     friend class AutoSymbolTable;
     friend class AutoLoopLevel;
     friend class AutoSwitchLevel;
     friend class Compiler;
 };
 
 }
 
 #endif