Add HostCachePersistenceManager for Cronet

net/dns/host_cache.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 "net/dns/host_cache.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 230 matching lines @@
   DCHECK_GT(max_entries_, size());
   DCHECK_EQ(0u, entries_.count(key));
   entries_.insert(std::make_pair(key, entry));
   DCHECK_GE(max_entries_, size());
 }
 
 void HostCache::OnNetworkChange() {
   ++network_changes_;
 }
 
+void HostCache::set_persistence_delegate(PersistenceDelegate* delegate) {
+  // A PersistenceDelegate shouldn't be added if there already was one, and
+  // shouldn't be removed (by setting to nullptr) if it wasn't previously there.
+  DCHECK_NE(delegate == nullptr, delegate_ == nullptr);
+  delegate_ = delegate;
+}
+
 void HostCache::clear() {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
   RecordEraseAll(ERASE_CLEAR, base::TimeTicks::Now());
 
   // Don't bother scheduling a write if there's nothing to clear.
   if (size() == 0)
     return;
 
   entries_.clear();
   if (delegate_)
@@ skipping 269 matching lines @@
     CACHE_HISTOGRAM_TIME("EraseValid.ValidFor", -stale.expired_by);
   }
 }
 
 void HostCache::RecordEraseAll(EraseReason reason, base::TimeTicks now) {
   for (const auto& it : entries_)
     RecordErase(reason, now, it.second);
 }
 
 }  // namespace net