Only check if a 'new' preference already exists in checking builds

chrome/browser/prefs/pref_service.cc

 // Copyright (c) 2012 The Chromium 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 "chrome/browser/prefs/pref_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 769 matching lines @@
 }
 
 void PrefService::RegisterPreference(const char* path,
                                      Value* default_value,
                                      PrefSyncStatus sync_status) {
   DCHECK(CalledOnValidThread());
 
   // The main code path takes ownership, but most don't. We'll be safe.
   scoped_ptr<Value> scoped_value(default_value);
 
-  if (FindPreference(path)) {
-    NOTREACHED() << "Tried to register duplicate pref " << path;
-    return;
-  }
+  DCHECK(!FindPreference(path)) << "Tried to register duplicate pref " << path;
 
   base::Value::Type orig_type = default_value->GetType();
   DCHECK(orig_type != Value::TYPE_NULL && orig_type != Value::TYPE_BINARY) <<
          "invalid preference type: " << orig_type;
 
   // For ListValue and DictionaryValue with non empty default, empty value
   // for |path| needs to be persisted in |user_pref_store_|. So that
   // non empty default is not used when user sets an empty ListValue or
   // DictionaryValue.
   bool needs_empty_value = false;
@@ skipping 256 matching lines @@
   return pref_value_store()->PrefValueFromDefaultStore(name_.c_str());
 }
 
 bool PrefService::Preference::IsUserModifiable() const {
   return pref_value_store()->PrefValueUserModifiable(name_.c_str());
 }
 
 bool PrefService::Preference::IsExtensionModifiable() const {
   return pref_value_store()->PrefValueExtensionModifiable(name_.c_str());
 }