Rewrite base::JSONReader to be 35-40% faster, depending on the input string.

chrome/browser/prefs/pref_model_associator.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_model_associator.h"
 
 #include "base/auto_reset.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/location.h"
@@ skipping 30 matching lines @@
   VLOG(1) << "Associating preference " << pref_name;
 
   base::JSONReader reader;
   if (sync_pref.IsValid()) {
     // The server has a value for the preference, we have to reconcile it with
     // ours.
     const sync_pb::PreferenceSpecifics& preference =
         sync_pref.GetSpecifics().preference();
     DCHECK_EQ(pref->name(), preference.name());
 
-    scoped_ptr<Value> value(
-        reader.JsonToValue(preference.value(), false, false));
+    scoped_ptr<Value> value(reader.ReadToValue(preference.value()));
     if (!value.get()) {
       LOG(ERROR) << "Failed to deserialize preference value: "
                  << reader.GetErrorMessage();
       return;
     }
 
     // Merge the server value of this preference with the local value.
     scoped_ptr<Value> new_value(MergePreference(*pref, *value));
 
     // Update the local preference based on what we got from the
@@ skipping 280 matching lines @@
       synced_preferences_.insert(name);
     }
   }
   return SyncError();
 }
 
 Value* PrefModelAssociator::ReadPreferenceSpecifics(
     const sync_pb::PreferenceSpecifics& preference,
     std::string* name) {
   base::JSONReader reader;
-  scoped_ptr<Value> value(reader.JsonToValue(preference.value(), false, false));
+  scoped_ptr<Value> value(reader.ReadToValue(preference.value()));
   if (!value.get()) {
     std::string err = "Failed to deserialize preference value: " +
         reader.GetErrorMessage();
     LOG(ERROR) << err;
     return NULL;
   }
   *name = preference.name();
   return value.release();
 }
 
@@ skipping 59 matching lines @@
   }
 
   SyncError error =
       sync_processor_->ProcessSyncChanges(FROM_HERE, changes);
 }
 
 void PrefModelAssociator::SetPrefService(PrefService* pref_service) {
   DCHECK(pref_service_ == NULL);
   pref_service_ = pref_service;
 }