MD History: Update sign in state in data source

chrome/browser/ui/webui/md_history_ui.h

Index: chrome/browser/ui/webui/md_history_ui.h
diff --git a/chrome/browser/ui/webui/md_history_ui.h b/chrome/browser/ui/webui/md_history_ui.h
index 024a91d0379b93683d0a88f10811220b2d1a6145..e3eb470336bfbb1dd6a9609d375350304fa30c8f 100644
--- a/chrome/browser/ui/webui/md_history_ui.h
+++ b/chrome/browser/ui/webui/md_history_ui.h
@@ -45,9 +45,16 @@ class MdHistoryUI : public content::WebUIController {
 
   static bool use_test_title_;
 
+  // Create and get the current valid data source.
+  content::WebUIDataSource* CreateAndGetDataSource();
+
   // Handler for the "menuPromoShown" message from the page. No arguments.
   void HandleMenuPromoShown(const base::ListValue* args);
 
+  // Callback method to update sign in state in data source when profile info
+  // changed.
+  void SignInChanged(bool signed_in);
+
   content::WebUIDataSource* data_source_;  // weak
 
   DISALLOW_COPY_AND_ASSIGN(MdHistoryUI);