MD History: Update sign in state in data source

chrome/browser/ui/webui/history_login_handler.h

Index: chrome/browser/ui/webui/history_login_handler.h
diff --git a/chrome/browser/ui/webui/history_login_handler.h b/chrome/browser/ui/webui/history_login_handler.h
index f10ab5259490ca892b6ede7097ea9e3550d082eb..82ceb744034235676d060e61a115fc842d389ea8 100644
--- a/chrome/browser/ui/webui/history_login_handler.h
+++ b/chrome/browser/ui/webui/history_login_handler.h
@@ -7,6 +7,7 @@
 
 #include <memory>
 
+#include "base/callback_forward.h"
 #include "base/macros.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
@@ -15,7 +16,7 @@ class ProfileInfoWatcher;
 // The handler for login-related messages from chrome://history.
 class HistoryLoginHandler : public content::WebUIMessageHandler {
  public:
-  HistoryLoginHandler();
+  explicit HistoryLoginHandler(const base::Closure& signin_callback);
   ~HistoryLoginHandler() override;
 
   // WebUIMessageHandler implementation.
@@ -35,6 +36,8 @@ class HistoryLoginHandler : public content::WebUIMessageHandler {
   // changes).
   std::unique_ptr<ProfileInfoWatcher> profile_info_watcher_;
 
+  base::Closure signin_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(HistoryLoginHandler);
 };