Add an update warning for downloading over mobile data

chrome/browser/ui/webui/help/version_updater_chromeos.h

Index: chrome/browser/ui/webui/help/version_updater_chromeos.h
diff --git a/chrome/browser/ui/webui/help/version_updater_chromeos.h b/chrome/browser/ui/webui/help/version_updater_chromeos.h
index b9f50dda92d8925a6eedf39a2e1be3611f5c845e..b6de0cb2f634fbf496a366d5f92d8346cc8a7b29 100644
--- a/chrome/browser/ui/webui/help/version_updater_chromeos.h
+++ b/chrome/browser/ui/webui/help/version_updater_chromeos.h
@@ -26,6 +26,9 @@ class VersionUpdaterCros : public VersionUpdater,
                   bool is_powerwash_allowed) override;
   void GetChannel(bool get_current_channel,
                   const ChannelCallback& callback) override;
+  void SetUpdateOverCellularTarget(const StatusCallback& callback,
+                                   const std::string& target_version,
+                                   int64_t target_size) override;
 
   // Gets the last update status, without triggering a new check or download.
   void GetUpdateStatus(const StatusCallback& callback);
@@ -47,6 +50,9 @@ class VersionUpdaterCros : public VersionUpdater,
   // Callback from UpdateEngineClient::RequestUpdateCheck().
   void OnUpdateCheck(chromeos::UpdateEngineClient::UpdateCheckResult result);
 
+  // Callback from UpdateEngineClient::SetUpdateOverCellularTarget().
+  void OnSetUpdateOverCellularTarget(bool success);
+
   // Callback from UpdateEngineClient::GetChannel().
   void OnGetChannel(const ChannelCallback& cb,
                     const std::string& current_channel);