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

src/heap/objects-visiting-inl.h

 // 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.
 
 #ifndef V8_OBJECTS_VISITING_INL_H_
 #define V8_OBJECTS_VISITING_INL_H_
 
 #include "src/heap/array-buffer-tracker.h"
 #include "src/heap/objects-visiting.h"
 #include "src/ic/ic-state.h"
@@ skipping 661 matching lines @@
   // If this is a full script wrapped in a function we do not flush the code.
   if (shared_info->is_toplevel()) {
     return false;
   }
 
   // The function must not be a builtin.
   if (shared_info->IsBuiltin()) {
     return false;
   }
 
+  // Maintain debug break slots in the code.
+  if (shared_info->HasDebugCode()) {
+    return false;
+  }
+
   // If this is a function initialized with %SetCode then the one-to-one
   // relation between SharedFunctionInfo and Code is broken.
   if (shared_info->dont_flush()) {
     return false;
   }
 
   // ----------------------------------------------------------------
   // The above predicates up to this line are hard invariants, below
   // this line are heuristics that should not affect correctness.
   // ----------------------------------------------------------------
@@ skipping 60 matching lines @@
   typedef FlexibleBodyVisitor<StaticVisitor, JSFunction::BodyDescriptorWeakCode,
                               void> JSFunctionWeakCodeBodyVisitor;
   JSFunctionWeakCodeBodyVisitor::Visit(map, object);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_VISITING_INL_H_