Convert indirect uses of TestingFactoryFunction

TestingFactoryFunction is a simple function pointer. It is
deprecated in favor of TestingFactory which is a Callback<>.
Convert indirect uses by using base::BindRepeating() in all
invocation of SetTestingFactory/AddTestingFactory.

This converts uses in src//chrome/browser/chromeos/extensions/users_private.

This CL was uploaded by git cl split.

R=emaxx@chromium.org

Bug: 809610
Change-Id: Ie2a188fc12106a28474818c9e57dc4dbac233841
Reviewed-on: https://chromium-review.googlesource.com/c/1258769Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597050}

chrome/browser/chromeos/extensions/users_private/users_private_apitest.cc

@@ -4,6 +4,7 @@
 
 #include <vector>
 
+#include "base/bind.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ -146,7 +147,8 @@ class UsersPrivateApiTest : public ExtensionApiTest {
       s_test_delegate_ = new TestDelegate(profile());
 
     UsersPrivateDelegateFactory::GetInstance()->SetTestingFactory(
-        profile(), &UsersPrivateApiTest::GetUsersPrivateDelegate);
+        profile(),
+        base::BindRepeating(&UsersPrivateApiTest::GetUsersPrivateDelegate));
     content::RunAllPendingInMessageLoop();
   }