Cache maps for slow case objects.

src/bootstrapper.cc

Index: src/bootstrapper.cc
===================================================================
--- src/bootstrapper.cc	(revision 5141)
+++ src/bootstrapper.cc	(working copy)
@@ -231,6 +231,7 @@
   bool InstallNatives();
   void InstallCustomCallGenerators();
   void InstallJSFunctionResultCaches();
+  void InitializeNormalizedMapCaches();
   // Used both for deserialized and from-scratch contexts to add the extensions
   // provided.
   static bool InstallExtensions(Handle<Context> global_context,
@@ -1392,6 +1393,13 @@
 }
 
 
+void Genesis::InitializeNormalizedMapCaches() {
+  Handle<FixedArray> array(
+      Factory::NewFixedArray(NormalizedMapCache::kEntries, TENURED));
+  global_context()->set_normalized_map_cache(NormalizedMapCache::cast(*array));
+}
+
+
 int BootstrapperActive::nesting_ = 0;
 
 
@@ -1758,6 +1766,7 @@
     HookUpGlobalProxy(inner_global, global_proxy);
     InitializeGlobal(inner_global, empty_function);
     InstallJSFunctionResultCaches();
+    InitializeNormalizedMapCaches();
     if (!InstallNatives()) return;
 
     MakeFunctionInstancePrototypeWritable();