Replace MessageLoop::DeleteSoon implementation with one that uses base::Bind.

net/url_request/url_request_context_getter.h

Index: net/url_request/url_request_context_getter.h
diff --git a/net/url_request/url_request_context_getter.h b/net/url_request/url_request_context_getter.h
index 88421f4f1e8169a99c6bed5d9e6e743f2103409b..a2475ddc174b060e4cd7fc656f0cc4de89a95506 100644
--- a/net/url_request/url_request_context_getter.h
+++ b/net/url_request/url_request_context_getter.h
@@ -7,7 +7,7 @@
 #pragma once
 
 #include "base/memory/ref_counted.h"
-#include "base/task.h"
+#include "base/message_loop_helpers.h"
 #include "net/base/net_export.h"
 
 namespace base {
@@ -40,7 +40,7 @@ class NET_EXPORT URLRequestContextGetter
  protected:
   friend class base::RefCountedThreadSafe<URLRequestContextGetter,
                                           URLRequestContextGetterTraits>;
-  friend class DeleteTask<const URLRequestContextGetter>;
+  friend class base::DeleteHelper<URLRequestContextGetter>;
   friend struct URLRequestContextGetterTraits;
 
   URLRequestContextGetter();