base::Bind: Convert FileUtilProxy::WriteCallback.

base/file_util_proxy.h

Index: base/file_util_proxy.h
diff --git a/base/file_util_proxy.h b/base/file_util_proxy.h
index 304854851b28f5759e5ca61af98e7dc01ded3c8a..146baa825a6cbdabfb0e41b2921926e8f329e5f4 100644
--- a/base/file_util_proxy.h
+++ b/base/file_util_proxy.h
@@ -55,8 +55,8 @@ class BASE_EXPORT FileUtilProxy {
   typedef base::Callback<void(PlatformFileError /* error code */,
                               const char* /* data */,
                               int /* bytes read/written */)> ReadCallback;
-  typedef Callback2<PlatformFileError /* error code */,
-                    int /* bytes written */>::Type WriteCallback;
+  typedef base::Callback<void(PlatformFileError /* error code */,
+                              int /* bytes written */)> WriteCallback;
 
   // Creates or opens a file with the given flags.  It is invalid to pass NULL
   // for the callback.
@@ -179,7 +179,7 @@ class BASE_EXPORT FileUtilProxy {
       int64 offset,
       const char* buffer,
       int bytes_to_write,
-      WriteCallback* callback);
+      const WriteCallback& callback);
 
   // Touches a file. The callback can be NULL.
   static bool Touch(