DCHECK tasks posted by TaskRunner::PostTask

base/deferred_sequenced_task_runner.cc

Index: base/deferred_sequenced_task_runner.cc
diff --git a/base/deferred_sequenced_task_runner.cc b/base/deferred_sequenced_task_runner.cc
index 3811bdaa82103d648b15910fbcd0a6db93a83517..926d895f0cb4d6dad3487b052b192ade642039b0 100644
--- a/base/deferred_sequenced_task_runner.cc
+++ b/base/deferred_sequenced_task_runner.cc
@@ -72,6 +72,8 @@ void DeferredSequencedTaskRunner::QueueDeferredTask(
     Closure task,
     TimeDelta delay,
     bool is_non_nestable) {
+  DCHECK(task);
+
   DeferredTask deferred_task;
   deferred_task.posted_from = from_here;
   deferred_task.task = std::move(task);