Use android chrome's time limit for chromeos chrome.

This cl cleans up old comment. Chrome on Chrome Os and
web apps' time limit are going to be set through
android chrome's time limit. This is because chrome browser
on Chrome Os and android chrome are represented together
in the Family Link app.

Bug: 1015661
Change-Id: Ib3ac4b0ab6109aba07a7e12c9bbeaf4493d5d68f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2071140
Commit-Queue: Yilkal Abe <yilkal@chromium.org>
Reviewed-by: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744347}

chrome/browser/chromeos/child_accounts/time_limits/app_activity_registry.cc

@@ -379,7 +379,8 @@ void AppActivityRegistry::UpdateAppLimits(
     if (is_web && base::Contains(app_limits, GetChromeAppId()))
       new_limit = app_limits.at(GetChromeAppId());
 
-    // TODO(yilkal): Clean up the following if statement after bug bash.
+    // In Family Link app Chrome on Chrome OS is combined together with Android
+    // Chrome. Therefore, use Android Chrome's time limit.
     if (is_web && !base::Contains(app_limits, GetChromeAppId()) &&
         base::Contains(app_limits, GetAndroidChromeAppId())) {
       new_limit = app_limits.at(GetAndroidChromeAppId());