Add a simple API around the pref controlling the default browser prompt.

chrome/browser/ui/startup/default_browser_prompt.h

Index: chrome/browser/ui/startup/default_browser_prompt.h
diff --git a/chrome/browser/ui/startup/default_browser_prompt.h b/chrome/browser/ui/startup/default_browser_prompt.h
index d009d57653a8ff876915762f759e6341f5f46478..ff395283acf03e5e3e54d82a4ba70ebd29f90c78 100644
--- a/chrome/browser/ui/startup/default_browser_prompt.h
+++ b/chrome/browser/ui/startup/default_browser_prompt.h
@@ -15,6 +15,13 @@ void RegisterDefaultBrowserPromptPrefs(PrefRegistrySimple* registry);
 // Shows a prompt UI to set the default browser if necessary.
 void ShowDefaultBrowserPrompt(Profile* profile);
 
+// Marks the default browser prompt as having been declined.
+void DefaultBrowserPromptDeclined(Profile* profile);
+
+// Resets the tracking preference for the default browser prompt so that it is
+// re-shown if the browser ceases to be the user's chosen default.
+void ResetDefaultBrowserPrompt(Profile* profile);
+
 // Shows a prompt UI to set the default browser on first run
 // (if necessary and permitted). Returns true if the dialog has been launched.
 bool ShowFirstRunDefaultBrowserPrompt(Profile* profile);