Remaining cleanup (base::Bind): Replacing FileUtilProxy calls with new callback

chrome/browser/extensions/sandboxed_extension_unpacker.cc

Index: chrome/browser/extensions/sandboxed_extension_unpacker.cc
diff --git a/chrome/browser/extensions/sandboxed_extension_unpacker.cc b/chrome/browser/extensions/sandboxed_extension_unpacker.cc
index 897f4ab492cdbd4e4fc3c4dd85119d64bec031aa..9a4c21efc2ef52998198f24f8054c6e73daae212 100644
--- a/chrome/browser/extensions/sandboxed_extension_unpacker.cc
+++ b/chrome/browser/extensions/sandboxed_extension_unpacker.cc
@@ -6,9 +6,10 @@
 
 #include <set>
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/base64.h"
 #include "base/file_util.h"
-#include "base/file_util_proxy.h"
 #include "base/json/json_value_serializer.h"
 #include "base/memory/scoped_handle.h"
 #include "base/message_loop.h"
@@ -223,11 +224,10 @@ void SandboxedExtensionUnpacker::Start() {
 }
 
 SandboxedExtensionUnpacker::~SandboxedExtensionUnpacker() {
-  base::FileUtilProxy::Delete(
-      BrowserThread::GetMessageLoopProxyForThread(thread_identifier_),
-      temp_dir_.Take(),
-      true,
-      NULL);
+  BrowserThread::GetMessageLoopProxyForThread(thread_identifier_)->PostTask(
+      FROM_HERE,
+      base::IgnoreReturn(base::Callback<bool(void)>(
+          base::Bind(&file_util::Delete, temp_dir_.Take(), true))));
 }
 
 bool SandboxedExtensionUnpacker::OnMessageReceived(