[heap] Remove ability to turn off code flushing on demand.

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/bits.h"
@@ skipping 408 matching lines @@
 void Heap::IncrementDeferredCount(v8::Isolate::UseCounterFeature feature) {
   deferred_counters_[feature]++;
 }
 
 
 void Heap::GarbageCollectionPrologue() {
   {
     AllowHeapAllocation for_the_first_part_of_prologue;
     gc_count_++;
 
-    if (FLAG_flush_code) {
-      mark_compact_collector()->EnableCodeFlushing(true);
-    }
-
 #ifdef VERIFY_HEAP
     if (FLAG_verify_heap) {
       Verify();
     }
 #endif
   }
 
   // Reset GC statistics.
   promoted_objects_size_ = 0;
   previous_semi_space_copied_object_size_ = semi_space_copied_object_size_;
@@ skipping 5660 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8