Use a TestBrowserThreadBundle in WebUIDataSourceTest

It uses the //net stack, ergo it needs to have a MessageLoop

BUG=395356

Review URL: https://codereview.chromium.org/444333002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288097 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/webui/web_ui_data_source_unittest.cc

@@ -6,6 +6,7 @@
 #include "base/memory/ref_counted_memory.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/webui/web_ui_data_source_impl.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "content/test/test_content_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -83,6 +84,7 @@ class WebUIDataSourceTest : public testing::Test {
     result_data_ = data;
   }
 
+  TestBrowserThreadBundle thread_bundle_;
   scoped_refptr<WebUIDataSourceImpl> source_;
   TestClient client_;
 };