[MessageLoop] Remove left behind TODO

Oops hadn't saved file locally before "git cl upload -c" for last patch
set @ https://chromium-review.googlesource.com/c/chromium/src/+/1153458

TBR=kylechar@chromium.org

Bug: None
Change-Id: I4466d287a80f4472b61da2017c28c01ff31c4dbb
Reviewed-on: https://chromium-review.googlesource.com/1155250Reviewed-by: Gabriel Charette <gab@chromium.org>
Reviewed-by: kylechar <kylechar@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579113}

base/message_loop/pending_task_queue.h

@@ -14,8 +14,6 @@ namespace internal {
 
 // Provides storage for tasks deferred by MessageLoop via DelayedQueue and
 // DeferredQueue.
-// TODO(gab): Rename to PendingTaskQueue after landing
-// https://crrev.com/1088762.
 class PendingTaskQueue {
  public:
   // Provides a read-write task queue.