Implement Double.toStringAsFixed.

runtime/lib/double.cc

Index: runtime/lib/double.cc
diff --git a/runtime/lib/double.cc b/runtime/lib/double.cc
index 303305e04e0721e00a1d88bdeb1807703b8c579c..00c68e823af1033d676c8ada5744f8cd8eaa93b8 100644
--- a/runtime/lib/double.cc
+++ b/runtime/lib/double.cc
@@ -7,6 +7,7 @@
 #include "vm/bootstrap_natives.h"
 
 #include "vm/bigint_operations.h"
+#include "vm/double_conversion.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
@@ -184,6 +185,33 @@ DEFINE_NATIVE_ENTRY(Double_toInt, 1) {
 }
 
 
+DEFINE_NATIVE_ENTRY(Double_toStringAsFixed, 2) {
+  const Double& arg = Double::CheckedHandle(arguments->At(0));
+  GET_NATIVE_ARGUMENT(Smi, fraction_digits, arguments->At(1));
+  double d = arg.value();
+  int fraction_digits_value = fraction_digits.Value();
+  String& result = String::Handle();
+  bool succeeded = DoubleToStringAsFixed(d, fraction_digits_value, result);
+  if (!succeeded) {
+    GrowableArray<const Object*> args;
+    args.Add(&String::ZoneHandle(String::New(
+        "Illegal arguments to double.toStringAsFixed")));
+    Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
+  }
+  arguments->SetReturn(result);
+}
+
+
+DEFINE_NATIVE_ENTRY(Double_toStringAsExponential, 2) {
+  UNIMPLEMENTED();
+}
+
+
+DEFINE_NATIVE_ENTRY(Double_toStringAsPrecision, 2) {
+  UNIMPLEMENTED();
+}
+
+
 DEFINE_NATIVE_ENTRY(Double_isInfinite, 1) {
   const Double& arg = Double::CheckedHandle(arguments->At(0));
   if (isinf(arg.value())) {