Add task runners to more tests

chrome/browser/ui/cocoa/task_manager_mac_unittest.mm

Index: chrome/browser/ui/cocoa/task_manager_mac_unittest.mm
diff --git a/chrome/browser/ui/cocoa/task_manager_mac_unittest.mm b/chrome/browser/ui/cocoa/task_manager_mac_unittest.mm
index 11919305bd0d1e67ccff85c437b6b6685d7a1a07..0b626d0e7e13fdc6b543d638cbaf79feb410b989 100644
--- a/chrome/browser/ui/cocoa/task_manager_mac_unittest.mm
+++ b/chrome/browser/ui/cocoa/task_manager_mac_unittest.mm
@@ -10,6 +10,7 @@
 #import "chrome/browser/ui/cocoa/cocoa_test_helper.h"
 #import "chrome/browser/ui/cocoa/task_manager_mac.h"
 #include "chrome/grit/generated_resources.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #import "testing/gtest_mac.h"
 #include "testing/platform_test.h"
@@ -42,6 +43,7 @@ class TestResource : public task_manager::Resource {
 }  // namespace
 
 class TaskManagerWindowControllerTest : public CocoaTest {
+  content::TestBrowserThreadBundle thread_bundle_;
 };
 
 // Test creation, to ensure nothing leaks or crashes.