Always allow ServiceRegistry to be used with UtilityProcessHosts.

extensions/test/extensions_unittests_main.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/path_service.h"
 #include "base/test/launcher/unit_test_launcher.h"
+#include "base/test/test_io_thread.h"
 #include "content/public/common/content_client.h"
 #include "content/public/test/content_test_suite_base.h"
 #include "content/public/test/unittest_test_suite.h"
 #include "extensions/common/constants.h"
 #include "extensions/common/extension_paths.h"
 #include "extensions/test/test_extensions_client.h"
 #include "mojo/edk/embedder/embedder.h"
+#include "mojo/edk/test/scoped_ipc_support.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gl/test/gl_surface_test_support.h"
 #include "url/url_util.h"
 
 namespace {
 
 const int kNumExtensionStandardURLSchemes = 2;
 const url::SchemeWithType kExtensionStandardURLSchemes[
     kNumExtensionStandardURLSchemes] = {
   {extensions::kExtensionScheme, url::SCHEME_WITHOUT_PORT},
@@ skipping 78 matching lines @@
   ui::ResourceBundle::CleanupSharedInstance();
   content::ContentTestSuiteBase::Shutdown();
 }
 
 }  // namespace
 
 int main(int argc, char** argv) {
   content::UnitTestTestSuite test_suite(new ExtensionsTestSuite(argc, argv));
 
   mojo::edk::Init();
+  base::TestIOThread test_io_thread(base::TestIOThread::kAutoStart);

[Reilly Grant (use Gerrit), 2016/03/31 23:18:31]

I'm a little nervous about adding this as there may be tests that want to create
a TestIOThread for their own purposes and the general assumption is that while
browser tests run with a mostly full environment unit tests do not.

There don't appear to be any tests that do this at the moment. How many tests in
this executable need Mojo IPC support?

+  mojo::edk::test::ScopedIPCSupport ipc_support(test_io_thread.task_runner());
+
   return base::LaunchUnitTests(argc,
                                argv,
                                base::Bind(&content::UnitTestTestSuite::Run,
                                           base::Unretained(&test_suite)));
 }