base: Remove non-const refs from the MRUCache implementation.

chrome/browser/ui/app_list/search/common/webservice_cache.cc

 // Copyright 2013 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/ui/app_list/search/common/webservice_cache.h"
 
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace app_list {
 namespace {
 
 const unsigned int kWebserviceCacheMaxSize = 1000;
 const unsigned int kWebserviceCacheTimeLimitInMinutes = 1;
 
 const char kKeyResultTime[] = "time";
 const char kKeyResult[] = "result";
 
 const char kWebstoreQueryPrefix[] = "webstore:";
 const char kPeopleQueryPrefix[] = "people:";
 
 }  // namespace
 
-void WebserviceCache::CacheDeletor::operator()(Payload& payload) {
+void WebserviceCache::CacheDeletor::operator()(const Payload& payload) {
   delete payload.result;
 }
 
 WebserviceCache::WebserviceCache(content::BrowserContext* context)
     : cache_(Cache::NO_AUTO_EVICT),
       cache_loaded_(false) {
   const char kStoreDataFileName[] = "Webservice Search Cache";
   const base::FilePath data_file =
       context->GetPath().AppendASCII(kStoreDataFileName);
   data_store_ = new DictionaryDataStore(
@@ skipping 117 matching lines @@
     case WEBSTORE:
       return kWebstoreQueryPrefix + query;
     case PEOPLE:
       return kPeopleQueryPrefix + query;
     default:
       return query;
   }
 }
 
 }  // namespace app_list