Use browsers JSON.parse for parsing JSON (#3)

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index b2dba5a4c7fcef7c894f80b7a774224e6e195f27..62f82e8f1adea49aa2d5533fc3fb667795b48008 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -1101,6 +1101,11 @@ RawError* Object::Init(Isolate* isolate) {
   INIT_LIBRARY(Json,
                Bootstrap::LoadJsonScript(false),
                Library::JsonLibrary());
+  patch_script = Bootstrap::LoadJsonScript(true);
+  error = lib.Patch(patch_script);
+  if (!error.IsNull()) {
+    return error.raw();
+  }
   INIT_LIBRARY(Utf,
                Bootstrap::LoadUtfScript(false),
                Library::UtfLibrary());