Add the chrome.fileSystem.onVolumeListChanged event.

chrome/browser/chromeos/extensions/file_manager/event_router.cc

Index: chrome/browser/chromeos/extensions/file_manager/event_router.cc
diff --git a/chrome/browser/chromeos/extensions/file_manager/event_router.cc b/chrome/browser/chromeos/extensions/file_manager/event_router.cc
index d58e6d6ddbb63065c0aee7b0838dc64162054687..1dca789715c367ef267629ba3d0af8b9a982a01a 100644
--- a/chrome/browser/chromeos/extensions/file_manager/event_router.cc
+++ b/chrome/browser/chromeos/extensions/file_manager/event_router.cc
@@ -26,6 +26,7 @@
 #include "chrome/browser/chromeos/login/lock/screen_locker.h"
 #include "chrome/browser/chromeos/login/ui/login_display_host_impl.h"
 #include "chrome/browser/drive/drive_service_interface.h"
+#include "chrome/browser/extensions/api/file_system/file_system_api.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile.h"
@@ -868,6 +869,11 @@ void EventRouter::OnVolumeMounted(chromeos::MountError error_code,
   DispatchMountCompletedEvent(
       file_manager_private::MOUNT_COMPLETED_EVENT_TYPE_MOUNT, error_code,
       volume);
+
+  // TODO(mtomasz): Move VolumeManager and part of the event router outside of
+  // file_manager, so there is no dependency between File System API and the
+  // file_manager code.
+  extensions::file_system_api::DispatchVolumeListChangeEvent(profile_);
 }
 
 void EventRouter::OnVolumeUnmounted(chromeos::MountError error_code,