Implement the new Sync Confirmation dialog on Linux and Windows.

chrome/browser/ui/views/frame/browser_view.h

Index: chrome/browser/ui/views/frame/browser_view.h
diff --git a/chrome/browser/ui/views/frame/browser_view.h b/chrome/browser/ui/views/frame/browser_view.h
index 04a95499c1200d1734a5ba9547af24113a31b200..2e63e9d6aff15f37b26748ef7838bf96f61138be 100644
--- a/chrome/browser/ui/views/frame/browser_view.h
+++ b/chrome/browser/ui/views/frame/browser_view.h
@@ -371,6 +371,7 @@ class BrowserView : public BrowserWindow,
   void ShowModalSigninWindow(AvatarBubbleMode mode,
                              signin_metrics::AccessPoint access_point) override;
   void CloseModalSigninWindow() override;
+  void ShowModalSyncConfirmationWindow() override;
   int GetRenderViewHeightInsetWithDetachedBookmarkBar() override;
   void ExecuteExtensionCommand(const extensions::Extension* extension,
                                const extensions::Command& command) override;