Change the API of disk_cache::CreateCacheBackend to use scoped_ptr

net/disk_cache/mem_backend_impl.h

Index: net/disk_cache/mem_backend_impl.h
diff --git a/net/disk_cache/mem_backend_impl.h b/net/disk_cache/mem_backend_impl.h
index bf15f6e44158e66ab632b8cb5d5383b7e8aa28de..8da39cc7f2607e922bd2e2d8a3998b54d91fb951 100644
--- a/net/disk_cache/mem_backend_impl.h
+++ b/net/disk_cache/mem_backend_impl.h
@@ -32,7 +32,7 @@ class NET_EXPORT_PRIVATE MemBackendImpl : public Backend {
   // size the cache can grow to. If zero is passed in as max_bytes, the cache
   // will determine the value to use based on the available memory. The returned
   // pointer can be NULL if a fatal error is found.
-  static Backend* CreateBackend(int max_bytes, net::NetLog* net_log);
+  static scoped_ptr<Backend> CreateBackend(int max_bytes, net::NetLog* net_log);
 
   // Performs general initialization for this current instance of the cache.
   bool Init();