Export a private webstore API to call into the new inline sign-in flow.

chrome/browser/signin/about_signin_internals.h

Index: chrome/browser/signin/about_signin_internals.h
diff --git a/chrome/browser/signin/about_signin_internals.h b/chrome/browser/signin/about_signin_internals.h
index 07cf96e1cc504ead6333be89c79328311472f7a7..682a009223dbe8988aa2bf337c064dccd7a86518 100644
--- a/chrome/browser/signin/about_signin_internals.h
+++ b/chrome/browser/signin/about_signin_internals.h
@@ -28,6 +28,7 @@ typedef std::pair<std::string, std::string> TimedSigninStatusValue;
 class AboutSigninInternals
     : public KeyedService,
       public signin_internals_util::SigninDiagnosticsObserver,
+      public SigninManagerFactory::Observer,
       public OAuth2TokenService::DiagnosticsObserver {
  public:
   class Observer {
@@ -53,11 +54,14 @@ class AboutSigninInternals
   virtual void NotifySigninValueChanged(
       const signin_internals_util::UntimedSigninStatusField& field,
       const std::string& value) OVERRIDE;
-
   virtual void NotifySigninValueChanged(
       const signin_internals_util::TimedSigninStatusField& field,
       const std::string& value) OVERRIDE;
 
+    // SigninManagerFactory::Observer implementation.
+  virtual void SigninManagerCreated(SigninManagerBase* manager) OVERRIDE;
+  virtual void SigninManagerShutdown(SigninManagerBase* manager) OVERRIDE;
+
   void Initialize(Profile* profile);
 
   // KeyedService implementation.