base/task: Require traits to be given to PostDelayedTask

This change makes it a requirement to pass in TaskTraits to
base::PostDelayedTask(), bringing it in line with the other task posting
APIs.

This patch has no functional changes.

Bug: 968047
Change-Id: I67daf3c1560f9c386578d458a45a3c791786141e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1985773
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Auto-Submit: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742786}

base/task/post_task.cc

@@ -71,13 +71,9 @@ TaskExecutor* GetTaskExecutorForTraits(const TaskTraits& traits) {
 }  // namespace
 
 bool PostTask(const Location& from_here, OnceClosure task) {
-  return PostDelayedTask(from_here, std::move(task), TimeDelta());
-}
-
-bool PostDelayedTask(const Location& from_here,
-                     OnceClosure task,
-                     TimeDelta delay) {
-  return PostDelayedTask(from_here, {ThreadPool()}, std::move(task), delay);
+  // TODO(skyostil): Make task traits required here too.
+  return PostDelayedTask(from_here, {ThreadPool()}, std::move(task),
+                         TimeDelta());
 }
 
 bool PostTaskAndReply(const Location& from_here,

base/task/post_task.h

@@ -106,14 +106,6 @@ inline bool PostTask(OnceClosure task,
   return PostTask(from_here, std::move(task));
 }
 
-// Equivalent to calling PostDelayedTask with default TaskTraits.
-//
-// Use PostDelayedTask to specify a BEST_EFFORT priority if the task doesn't
-// have to run as soon as |delay| expires.
-BASE_EXPORT bool PostDelayedTask(const Location& from_here,
-                                 OnceClosure task,
-                                 TimeDelta delay);
-
 // Equivalent to calling PostTaskAndReply with default TaskTraits.
 BASE_EXPORT bool PostTaskAndReply(const Location& from_here,
                                   OnceClosure task,