Explicitly wait for user policy before completing login.

chrome/browser/policy/user_policy_cache.h

Index: chrome/browser/policy/user_policy_cache.h
diff --git a/chrome/browser/policy/user_policy_cache.h b/chrome/browser/policy/user_policy_cache.h
index c98adfefbf0ec4cf33e79dba75932eaf35c06daf..c91a25bbb6c3e2f9c82afc56b411a26d58b950ce 100644
--- a/chrome/browser/policy/user_policy_cache.h
+++ b/chrome/browser/policy/user_policy_cache.h
@@ -8,6 +8,7 @@
 
 #include <string>
 
+#include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
@@ -37,8 +38,10 @@ class UserPolicyCache : public CloudPolicyCacheBase,
   // |backing_file_path| is the path to the cache file.
   // |wait_for_policy_fetch| is true if the cache should be ready only after
   // an attempt was made to fetch user policy.
+  // If |callback| is not null, it will be invoked once the cache is ready.
   UserPolicyCache(const FilePath& backing_file_path,
-                  bool wait_for_policy_fetch);
+                  bool wait_for_policy_fetch,
+                  const base::Closure& callback);
   virtual ~UserPolicyCache();
 
   // CloudPolicyCacheBase implementation:
@@ -94,6 +97,9 @@ class UserPolicyCache : public CloudPolicyCacheBase,
   // fetched policy, or if there is no need to wait for that.
   bool fetch_ready_;
 
+  // Callback to invoke when the cache becomes ready.
+  base::Closure ready_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(UserPolicyCache);
 };