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..d8f0ef12506b096cf3e98c6b6fc152edfc37a2a9 100644
--- a/chrome/browser/ui/webui/md_history_ui.h
+++ b/chrome/browser/ui/webui/md_history_ui.h
@@ -17,9 +17,6 @@ class ListValue;
 class RefCountedMemory;
 }
 
-namespace content {
-class WebUIDataSource;
-}
 
 namespace user_prefs {
 class PrefRegistrySyncable;
@@ -45,10 +42,13 @@ class MdHistoryUI : public content::WebUIController {
 
   static bool use_test_title_;
 
+  void CreateDataSource();
+
   // Handler for the "menuPromoShown" message from the page. No arguments.
   void HandleMenuPromoShown(const base::ListValue* args);
 
-  content::WebUIDataSource* data_source_;  // weak
+  // Callback method to recreate data source when profile info changed.
+  void SignInChanged();
 
   DISALLOW_COPY_AND_ASSIGN(MdHistoryUI);
 };