Avoid unneeded refcount bump on disk_cache::File

net/disk_cache/blockfile/file_posix.cc

Index: net/disk_cache/blockfile/file_posix.cc
diff --git a/net/disk_cache/blockfile/file_posix.cc b/net/disk_cache/blockfile/file_posix.cc
index 828200588a9b66ac7a9d2ec14e304cca6a354c54..1297cf07144d3910f0242802f544c79f438b0a79 100644
--- a/net/disk_cache/blockfile/file_posix.cc
+++ b/net/disk_cache/blockfile/file_posix.cc
@@ -97,7 +97,8 @@ bool File::Read(void* buffer, size_t buffer_len, size_t offset,
 
   base::PostTaskAndReplyWithResult(
       s_worker_pool.Pointer(), FROM_HERE,
-      base::Bind(&File::DoRead, this, buffer, buffer_len, offset),
+      base::Bind(&File::DoRead, base::Unretained(this), buffer, buffer_len,
+                 offset),
       base::Bind(&File::OnOperationComplete, this, callback));
 
   *completed = false;
@@ -120,7 +121,8 @@ bool File::Write(const void* buffer, size_t buffer_len, size_t offset,
 
   base::PostTaskAndReplyWithResult(
       s_worker_pool.Pointer(), FROM_HERE,
-      base::Bind(&File::DoWrite, this, buffer, buffer_len, offset),
+      base::Bind(&File::DoWrite, base::Unretained(this), buffer, buffer_len,
+                 offset),
       base::Bind(&File::OnOperationComplete, this, callback));
 
   *completed = false;