Remove unnecessary TODO in browser_thread.h

As discussed @ https://crbug.com/878356#c39

R=thestig@chromium.org

Bug: 878356
Change-Id: I7f9df5e84384c4f0c61a4ac02624fec54e6d9a27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1822419Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Auto-Submit: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699829}

content/public/browser/browser_thread.h

@@ -69,8 +69,13 @@ class CONTENT_EXPORT BrowserThread {
   // NOTE: Task posting APIs have moved to post_task.h. See
   // browser_task_traits.h.
 
-  // TODO(crbug.com/878356): Consider replacing callsites of this with
-  // base::CreateTaskRunner({id})->DeleteSoon(..).
+  // Delete/ReleaseSoon() helpers allow future deletion of an owned object on
+  // its associated thread. If you already have a task runner bound to a
+  // BrowserThread you should use its SequencedTaskRunner::DeleteSoon() member
+  // method. If you don't, the helpers below avoid having to do
+  // base::CreateSingleThreadTaskRunner({BrowserThread::ID})->DeleteSoon(...)
+  // which is equivalent.
+
   template <class T>
   static bool DeleteSoon(ID identifier,
                          const base::Location& from_here,

ios/web/public/thread/web_thread.h

@@ -67,8 +67,13 @@ class WebThread {
 
   // NOTE: Task posting APIs have moved to post_task.h. See web_task_traits.h.
 
-  // TODO(crbug.com/878356): Consider replacing callsites of this with
-  // base::CreateTaskRunner({id})->DeleteSoon(..).
+  // Delete/ReleaseSoon() helpers allow future deletion of an owned object on
+  // its associated thread. If you already have a task runner bound to a
+  // WebThread you should use its SequencedTaskRunner::DeleteSoon() member
+  // method. If you don't, the helpers below avoid having to do
+  // base::CreateSingleThreadTaskRunner({WebThread::ID})->DeleteSoon(...) which
+  // is equivalent.
+
   template <class T>
   static bool DeleteSoon(ID identifier,
                          const base::Location& from_here,