Move update state bits under changed branch

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 2718 matching lines @@
 
 
 void Class::DisableCHAOptimizedCode() {
   CHACodeArray a(*this);
   a.DisableCode();
 }
 
 
 void Class::SetTraceAllocation(bool trace_allocation) const {
   const bool changed = trace_allocation != this->trace_allocation();
-  set_state_bits(
-      TraceAllocationBit::update(trace_allocation, raw_ptr()->state_bits_));
   if (changed) {
+    set_state_bits(
+        TraceAllocationBit::update(trace_allocation, raw_ptr()->state_bits_));
     Isolate* isolate = Isolate::Current();
     ClassTable* class_table = isolate->class_table();
     class_table->TraceAllocationsFor(id(), trace_allocation);
     DisableAllocationStub();
   }
 }
 
 
 void Class::set_cha_codes(const Array& cache) const {
   StorePointer(&raw_ptr()->cha_codes_, cache.raw());
@@ skipping 18446 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart