Ensure tests have an active task runner

chrome/browser/bitmap_fetcher/bitmap_fetcher_service_unittest.cc

Index: chrome/browser/bitmap_fetcher/bitmap_fetcher_service_unittest.cc
diff --git a/chrome/browser/bitmap_fetcher/bitmap_fetcher_service_unittest.cc b/chrome/browser/bitmap_fetcher/bitmap_fetcher_service_unittest.cc
index 73513c87ba68e4a9ee3bc3bb1e2aa8c99aecbb1c..90dbf329377a0d62aaf4dd27d5b9e9da6a3a4d99 100644
--- a/chrome/browser/bitmap_fetcher/bitmap_fetcher_service_unittest.cc
+++ b/chrome/browser/bitmap_fetcher/bitmap_fetcher_service_unittest.cc
@@ -6,6 +6,7 @@
 
 #include "chrome/browser/bitmap_fetcher/bitmap_fetcher.h"
 #include "chrome/test/base/testing_profile.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
@@ -97,6 +98,7 @@ class BitmapFetcherServiceTest : public testing::Test,
   GURL url2_;
 
  private:
+  content::TestBrowserThreadBundle thread_bundle_;
   TestingProfile profile_;
 };