Show "Update Chrome OS" in the wrench menu, when the update image is ready.

chrome/browser/dom_ui/options/about_page_handler.h

Index: chrome/browser/dom_ui/options/about_page_handler.h
diff --git a/chrome/browser/dom_ui/options/about_page_handler.h b/chrome/browser/dom_ui/options/about_page_handler.h
index 2e4a76085c209722a3e779fe10b281452b312099..cd1005230cfbc94788eea4e5560935472a0730e9 100644
--- a/chrome/browser/dom_ui/options/about_page_handler.h
+++ b/chrome/browser/dom_ui/options/about_page_handler.h
@@ -29,7 +29,12 @@ class AboutPageHandler : public OptionsPageUIHandler {
   void PageReady(const ListValue* args);
 
 #if defined(OS_CHROMEOS)
+  // Initiates update check.
   void CheckNow(const ListValue* args);
+
+  // Restarts the system.
+  void RestartNow(const ListValue* args);
+
   // Callback from chromeos::VersionLoader giving the version.
   void OnOSVersion(chromeos::VersionLoader::Handle handle,
                    std::string version);