Change the API of disk_cache::CreateCacheBackend to use scoped_ptr

net/disk_cache/mem_backend_impl.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/disk_cache/mem_backend_impl.h"
 
 #include "base/logging.h"
 #include "base/sys_info.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/cache_util.h"
@@ skipping 23 matching lines @@
 MemBackendImpl::~MemBackendImpl() {
   EntryMap::iterator it = entries_.begin();
   while (it != entries_.end()) {
     it->second->Doom();
     it = entries_.begin();
   }
   DCHECK(!current_size_);
 }
 
 // Static.
-Backend* MemBackendImpl::CreateBackend(int max_bytes, net::NetLog* net_log) {
-  MemBackendImpl* cache = new MemBackendImpl(net_log);
+scoped_ptr<Backend> MemBackendImpl::CreateBackend(int max_bytes,
+                                                  net::NetLog* net_log) {
+  scoped_ptr<MemBackendImpl> cache(new MemBackendImpl(net_log));
   cache->SetMaxSize(max_bytes);
   if (cache->Init())
-    return cache;
+    return cache.PassAs<Backend>();
 
-  delete cache;
   LOG(ERROR) << "Unable to create cache";
-  return NULL;
+  return scoped_ptr<Backend>();
 }
 
 bool MemBackendImpl::Init() {
   if (max_size_)
     return true;
 
   int64 total_memory = base::SysInfo::AmountOfPhysicalMemory();
 
   if (total_memory <= 0) {
     max_size_ = kDefaultCacheSize;
@@ skipping 265 matching lines @@
   if (current_size_ > max_size_)
     TrimCache(false);
 }
 
 void MemBackendImpl::SubstractStorageSize(int32 bytes) {
   current_size_ -= bytes;
   DCHECK_GE(current_size_, 0);
 }
 
 }  // namespace disk_cache