Show GAIA/cookie accounts on the signin-internals page.

components/signin/core/browser/signin_client.h

Index: components/signin/core/browser/signin_client.h
diff --git a/components/signin/core/browser/signin_client.h b/components/signin/core/browser/signin_client.h
index 8668ab629781d5af3ce3d60fdb5d7bcadd0cfe5f..200c2dcff4bcbd76f3051a13165c2fdc2faa7a71 100644
--- a/components/signin/core/browser/signin_client.h
+++ b/components/signin/core/browser/signin_client.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_CLIENT_H_
 
 #include "base/callback.h"
+#include "base/callback_list.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/signin/core/browser/webdata/token_web_data.h"
 
@@ -33,6 +34,9 @@ class SigninClient : public KeyedService {
   typedef base::Callback<void(const net::CanonicalCookie* cookie)>
       CookieChangedCallback;
 
+  typedef base::CallbackList<void(const net::CanonicalCookie* cookie)>
+      CookieChangedCallbackList;
+
   virtual ~SigninClient() {}
 
   // Gets the preferences associated with the client.
@@ -65,13 +69,12 @@ class SigninClient : public KeyedService {
   // Signin component is being used.
   virtual std::string GetProductVersion() = 0;
 
-  // Sets the callback that should be called when a cookie changes. The
-  // callback will be called only if it is not empty.
+  // Adds or removes a callback that should be called when a cookie changes.
   // TODO(blundell): Eliminate this interface in favor of having core signin
   // code observe cookie changes once //chrome/browser/net has been
   // componentized.
-  virtual void SetCookieChangedCallback(
-      const CookieChangedCallback& callback) = 0;
+  virtual scoped_ptr<CookieChangedCallbackList::Subscription>
+      AddCookieChangedCallback(const CookieChangedCallback& callback) = 0;
 
   // Called when Google signin has succeeded.
   virtual void GoogleSigninSucceeded(const std::string& username,