MD History: Update sign in state in data source

chrome/browser/ui/webui/history_ui.h

Index: chrome/browser/ui/webui/history_ui.h
diff --git a/chrome/browser/ui/webui/history_ui.h b/chrome/browser/ui/webui/history_ui.h
index 13b012cde9ad1b887ad29a83066a495ad4377469..678d653d4ddfe2e889bdd425c40281c1aa8d42b6 100644
--- a/chrome/browser/ui/webui/history_ui.h
+++ b/chrome/browser/ui/webui/history_ui.h
@@ -15,6 +15,10 @@ namespace base {
 class RefCountedMemory;
 }
 
+namespace content {
+class WebUIDataSource;
+}
+
 class HistoryUI : public content::WebUIController {
  public:
   explicit HistoryUI(content::WebUI* web_ui);
@@ -24,6 +28,13 @@ class HistoryUI : public content::WebUIController {
       ui::ScaleFactor scale_factor);
 
  private:
+  // Create and get the current valid data source.
+  content::WebUIDataSource* CreateAndGetDataSource();
+
+  // Callback method to update sign in state in data source when profile info
+  // changed.
+  void SignInChanged(bool signed_in);
+
   DISALLOW_COPY_AND_ASSIGN(HistoryUI);
 };