Remove an obsolete comment in chrome_browser_main_chromeos.cc

There is no more ShouldShowMergeSessionPage, so the comment speaking about it is no longer needed.

NOTRY=true
BUG=243364

Review URL: https://codereview.chromium.org/138063002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245155 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

@@ -744,10 +744,7 @@ void ChromeBrowserMainPartsChromeos::PostMainMessageLoopRun() {
   KioskAppManager::Shutdown();
 
   // We first call PostMainMessageLoopRun and then destroy UserManager, because
-  // Ash needs to be closed before UserManager is destroyed. Also, on some tests
-  // MergeSessionThrottle::ShouldShowMergeSessionPage gets triggered during
-  // PostMainMessageLoopRun, which also requires UserManager to live (see
-  // http://crbug.com/243364).
+  // Ash needs to be closed before UserManager is destroyed.
   ChromeBrowserMainPartsLinux::PostMainMessageLoopRun();
 
   // Called after