Crankshaft is now able to compile top level code even if there is a ScriptContext.

src/contexts.cc

Index: src/contexts.cc
diff --git a/src/contexts.cc b/src/contexts.cc
index 37021ac7f67f789e33bdf6f91d876fc99eb4c551..d66a33043424c6cb13fc15214e3a97c4f3f36243 100644
--- a/src/contexts.cc
+++ b/src/contexts.cc
@@ -18,7 +18,7 @@ Handle<ScriptContextTable> ScriptContextTable::Extend(
   int used = table->used();
   int length = table->length();
   CHECK(used >= 0 && length > 0 && used < length);
-  if (used + 1 == length) {
+  if (used + kFirstContextSlot == length) {
     CHECK(length < Smi::kMaxValue / 2);
     Isolate* isolate = table->GetIsolate();
     Handle<FixedArray> copy =
@@ -31,7 +31,7 @@ Handle<ScriptContextTable> ScriptContextTable::Extend(
   result->set_used(used + 1);
 
   DCHECK(script_context->IsScriptContext());
-  result->set(used + 1, *script_context);
+  result->set(used + kFirstContextSlot, *script_context);
   return result;
 }