Lock the prototype of internal classes.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 9d3bb1d83b567480be63d4e4a355beecc636441e..dd82f7288d58907e5bd65594e7e969acc5c658fe 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -32,6 +32,7 @@
 #include "accessors.h"
 #include "api.h"
 #include "arguments.h"
+#include "bootstrapper.h"
 #include "codegen.h"
 #include "compilation-cache.h"
 #include "compiler.h"
@@ -2147,6 +2148,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionIsBuiltin) {
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetCode) {
+  RUNTIME_ASSERT(isolate->bootstrapper()->IsActive());
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
 
@@ -8250,6 +8252,12 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_CompileForOnStackReplacement) {
 }
 
 
+RUNTIME_FUNCTION(MaybeObject*, Runtime_AssertIsBootstrapping) {
+  RUNTIME_ASSERT(isolate->bootstrapper()->IsActive());
+  return isolate->heap()->undefined_value();
+}
+
+
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFunctionDelegate) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);