Lazily initialize fast_sqrt() and pass an Isolate parameter to it

src/codegen.h

Index: src/codegen.h
diff --git a/src/codegen.h b/src/codegen.h
index c145c223e213f1e8a58502d875a8a7c601156126..dff766a6ea45cdcffddcb8e68dfc48e51465aaf2 100644
--- a/src/codegen.h
+++ b/src/codegen.h
@@ -89,23 +89,22 @@ class CodeGenerator {
 // Results of the library implementation of transcendental functions may differ
 // from the one we use in our generated code.  Therefore we use the same
 // generated code both in runtime and compiled code.
-typedef double (*UnaryMathFunction)(double x);
 typedef double (*UnaryMathFunctionWithIsolate)(double x, Isolate* isolate);
 
 UnaryMathFunctionWithIsolate CreateExpFunction(Isolate* isolate);
-UnaryMathFunction CreateSqrtFunction();
+UnaryMathFunctionWithIsolate CreateSqrtFunction(Isolate* isolate);
 
 
 double modulo(double x, double y);
 
 // Custom implementation of math functions.
 double fast_exp(double input, Isolate* isolate);
-double fast_sqrt(double input);
+double fast_sqrt(double input, Isolate* isolate);
 #ifdef _WIN64
 void init_modulo_function();
 #endif
 void lazily_initialize_fast_exp(Isolate* isolate);
-void init_fast_sqrt_function();
+void lazily_initialize_fast_sqrt(Isolate* isolate);
 
 
 class ElementsTransitionGenerator : public AllStatic {