Don't need to protect pregenerated stubs from flushing from the

src/stub-cache.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1091 matching lines @@
   if (!probe->IsUndefined()) return probe;
   StubCompiler compiler;
   return FillCache(isolate_, compiler.CompileCallDebugPrepareStepIn(flags));
 }
 #endif
 
 
 void StubCache::Clear() {
   Code* empty = isolate_->builtins()->builtin(Builtins::kIllegal);
   for (int i = 0; i < kPrimaryTableSize; i++) {
-    Code* code = primary_[i].value;
-    if (code != empty && !code->is_pregenerated()) {
-      primary_[i].key = heap()->empty_string();
-      primary_[i].value = empty;
-    }
+    primary_[i].key = heap()->empty_string();
+    primary_[i].value = empty;
   }
   for (int j = 0; j < kSecondaryTableSize; j++) {
-    Code* code = secondary_[j].value;
-    if (code != empty && !code->is_pregenerated()) {
-      secondary_[j].key = heap()->empty_string();
-      secondary_[j].value = empty;
-    }
+    secondary_[j].key = heap()->empty_string();
+    secondary_[j].value = empty;
   }
 }
 
 
 void StubCache::CollectMatchingMaps(SmallMapList* types,
                                     String* name,
                                     Code::Flags flags) {
   for (int i = 0; i < kPrimaryTableSize; i++) {
     if (primary_[i].key == name) {
       Map* map = primary_[i].value->FindFirstMap();
@@ skipping 712 matching lines @@
       expected_receiver_type_ =
           FunctionTemplateInfo::cast(signature->receiver());
     }
   }
 
   is_simple_api_call_ = true;
 }
 
 
 } }  // namespace v8::internal