Ensure tests have an active task runner

chrome/browser/autocomplete/bookmark_provider_unittest.cc

Index: chrome/browser/autocomplete/bookmark_provider_unittest.cc
diff --git a/chrome/browser/autocomplete/bookmark_provider_unittest.cc b/chrome/browser/autocomplete/bookmark_provider_unittest.cc
index 4afa6bebb3ff98cbcbe174f9c62a2ee224352dec..e9ba234a179820e58c9896e4dbdc26104a9ba08c 100644
--- a/chrome/browser/autocomplete/bookmark_provider_unittest.cc
+++ b/chrome/browser/autocomplete/bookmark_provider_unittest.cc
@@ -21,6 +21,7 @@
 #include "components/bookmarks/test/test_bookmark_client.h"
 #include "components/metrics/proto/omnibox_event.pb.h"
 #include "components/omnibox/autocomplete_provider.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using bookmarks::BookmarkMatch;
@@ -74,6 +75,7 @@ class BookmarkProviderTest : public testing::Test {
  protected:
   void SetUp() override;
 
+  content::TestBrowserThreadBundle thread_bundle_;
   bookmarks::TestBookmarkClient client_;
   scoped_ptr<TestingProfile> profile_;
   scoped_ptr<BookmarkModel> model_;