[Cleanup] Remove TODO to delete ChromeNotificationBuilder

- Presubmit still enforces that this interface is used instead of
Notification(Compat).Builders directly - the main benefit being that
it's harder to forget to initialize a notification channel, since both
implementations initialize the channel in their constructors.

- We'd like to keep this presubmit and this class may yet be used for
even greater purposes, hence removing the TODO since it's not going
away any time soon.

R=peter@chromium.org

Change-Id: Id6f4d80b37763b3a44a4a2d94dd1f6c6958a99da
Reviewed-on: https://chromium-review.googlesource.com/1160641Reviewed-by: Peter Beverloo <peter@chromium.org>
Commit-Queue: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580177}

chrome/android/java/src/org/chromium/chrome/browser/notifications/ChromeNotificationBuilder.java

@@ -14,8 +14,6 @@ import android.widget.RemoteViews;
 
 /**
  * Abstraction over Notification.Builder and NotificationCompat.Builder interfaces.
- *
- * TODO(awdf) Remove this once we've updated to revision 26 of the support library.
  */
 public interface ChromeNotificationBuilder {
     ChromeNotificationBuilder setAutoCancel(boolean autoCancel);