TaskScheduler: Add TaskRunnerHandle support to TaskScheduler tasks

base/task_scheduler/test_task_factory.h

Index: base/task_scheduler/test_task_factory.h
diff --git a/base/task_scheduler/test_task_factory.h b/base/task_scheduler/test_task_factory.h
index 9a11882209b20ae559197b4e638b6692f23490cf..01bd88fc28f18a36ecb0c284e3710581b5db0bf1 100644
--- a/base/task_scheduler/test_task_factory.h
+++ b/base/task_scheduler/test_task_factory.h
@@ -26,10 +26,12 @@ namespace test {
 
 // A TestTaskFactory posts tasks to a TaskRunner and verifies that they run as
 // expected. Generates a test failure when:
+// - The TaskRunnerHandles set in the context of the task don't match what's
+//   expected for the tested ExecutionMode.
 // - The ExecutionMode of the TaskRunner is SEQUENCED or SINGLE_THREADED and
 //   Tasks don't run in posting order.
-// - The ExecutionMode of the TaskRunner is SINGLE_THREADED and Tasks don't
-//   run on the same thread.
+// - The ExecutionMode of the TaskRunner is SINGLE_THREADED and Tasks don't run
+//   on the same thread.
 // - A Task runs more than once.
 class TestTaskFactory {
  public: