Implemented a "Last Updated" field for the about page of Chrome OS.

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

Index: chrome/browser/ui/webui/help/help_handler.h
diff --git a/chrome/browser/ui/webui/help/help_handler.h b/chrome/browser/ui/webui/help/help_handler.h
index 75341282380cc706621c5533182c167ccae9fc1b..db61f7a46ce1eb099e7618b11e0cf8c649d7e954 100644
--- a/chrome/browser/ui/webui/help/help_handler.h
+++ b/chrome/browser/ui/webui/help/help_handler.h
@@ -14,6 +14,8 @@
 #include "content/public/browser/web_ui_message_handler.h"
 
 #if defined(OS_CHROMEOS)
+#include "base/memory/weak_ptr.h"
+#include "base/platform_file.h"
 #include "chrome/browser/chromeos/version_loader.h"
 #endif  // defined(OS_CHROMEOS)
 
@@ -72,6 +74,9 @@ class HelpHandler : public content::WebUIMessageHandler,
   void OnOSFirmware(chromeos::VersionLoader::Handle handle,
                     std::string firmware);
   void OnReleaseChannel(const std::string& channel);
+
+  void ProcessLsbFileInfo(
+      base::PlatformFileError rv, const base::PlatformFileInfo& file_info);
 #endif
 
   // Specialized instance of the VersionUpdater used to update the browser.
@@ -81,6 +86,9 @@ class HelpHandler : public content::WebUIMessageHandler,
   content::NotificationRegistrar registrar_;
 
 #if defined(OS_CHROMEOS)
+  // Used for callbacks.
+  base::WeakPtrFactory<HelpHandler> weak_factory_;
+
   // Handles asynchronously loading the CrOS version info.
   chromeos::VersionLoader loader_;