Update comments for why disabling native notifications for old OS builds

Change-Id: I76106686b24889ef34a436bef00f5a8fc2641696
Reviewed-on: https://chromium-review.googlesource.com/c/1341480Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: Xi Cheng <chengx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609416}

chrome/browser/notifications/notification_platform_bridge_win.cc

@@ -868,9 +868,11 @@ bool NotificationPlatformBridgeWin::HandleActivation(
 
 // static
 bool NotificationPlatformBridgeWin::NativeNotificationEnabled() {
-  // Windows 10 native notification seems to have memory leak issues on OS
-  // builds older than 17134 (i.e., VERSION_WIN10_RS4). This seems to be a
-  // Windows issue which has been fixed in 17134.
+  // There was a Microsoft bug in Windows 10 prior to build 17134 (i.e.,
+  // VERSION_WIN10_RS4), causing endless loops in displaying notifications. It
+  // significantly amplified the memory and CPU usage. Therefore, we enable
+  // Windows 10 native notification only for build 17134 and later. See
+  // crbug.com/882622 and crbug.com/878823 for more details.
   return base::win::GetVersion() >= base::win::VERSION_WIN10_RS4 &&
          base::FeatureList::IsEnabled(features::kNativeNotifications);
 }