Show notifications on low disk space.

chrome/browser/chromeos/chrome_browser_main_chromeos.h

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.h
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.h b/chrome/browser/chromeos/chrome_browser_main_chromeos.h
index eb33f493433b56dc84195f846a2b3902441676b2..2de1fad257922aba221cf0ad090a678bd23b1102 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.h
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.h
@@ -27,6 +27,7 @@ class DataPromoNotification;
 class EventRewriter;
 class EventRewriterController;
 class IdleActionWarningObserver;
+class LowDiskNotification;
 class MagnificationManager;
 class PeripheralBatteryObserver;
 class PowerButtonObserver;
@@ -85,6 +86,8 @@ class ChromeBrowserMainPartsChromeos : public ChromeBrowserMainPartsLinux {
 
   std::unique_ptr<arc::ArcServiceLauncher> arc_service_launcher_;
 
+  std::unique_ptr<LowDiskNotification> low_disk_notification_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainPartsChromeos);
 };