Implement the gaia captcha state and unlock capability in the sync setup wiza...

chrome/browser/sync/engine/auth_watcher.h

Index: chrome/browser/sync/engine/auth_watcher.h
===================================================================
--- chrome/browser/sync/engine/auth_watcher.h	(revision 31575)
+++ chrome/browser/sync/engine/auth_watcher.h	(working copy)
@@ -106,6 +106,10 @@
 
   // The following 3 flavors of authentication routines are asynchronous and can
   // be called from any thread.
+  // If |captcha_value| is specified but |captcha_token| is not, this will
+  // attempt authentication using the last observed captcha token out of
+  // convenience in the common case so the token doesn't have to be plumbed
+  // everywhere.
   void Authenticate(const std::string& email, const std::string& password,
       const std::string& captcha_token, const std::string& captcha_value,
       bool persist_creds_to_disk);
@@ -171,13 +175,13 @@
   // A struct to marshal various data across to the auth_backend_thread_ on
   // Authenticate() and AuthenticateWithToken calls.
   struct AuthRequest {
-      std::string email;
-      std::string password;
-      std::string auth_token;
-      std::string captcha_token;
-      std::string captcha_value;
-      bool persist_creds_to_disk;
-      AuthWatcherEvent::AuthenticationTrigger trigger;
+    std::string email;
+    std::string password;
+    std::string auth_token;
+    std::string captcha_token;
+    std::string captcha_value;
+    bool persist_creds_to_disk;
+    AuthWatcherEvent::AuthenticationTrigger trigger;
   };
 
   // The public interface Authenticate methods are proxies to these, which