ComponentCloudPolicyService tracks the signin state.

chrome/browser/policy/cloud/component_cloud_policy_store.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/policy/cloud/component_cloud_policy_store.h"
 
 #include "base/callback.h"
 #include "base/json/json_reader.h"
 #include "base/logging.h"
 #include "base/sha1.h"
@@ skipping 213 matching lines @@
       cached_hashes_.erase(prev);
     } else {
       ++it;
     }
   }
 
   if (purged_current_policies)
     delegate_->OnComponentCloudPolicyStoreUpdated();
 }
 
+void ComponentCloudPolicyStore::Clear() {
+  for (size_t i = 0; i < arraysize(kDomains); ++i) {
+    cache_->Clear(kDomains[i].proto_cache_key);
+    cache_->Clear(kDomains[i].data_cache_key);
+  }
+  cached_hashes_.clear();
+  const PolicyBundle empty_bundle;
+  if (!policy_bundle_.Equals(empty_bundle)) {
+    policy_bundle_.Clear();
+    delegate_->OnComponentCloudPolicyStoreUpdated();
+  }
+}
+
 bool ComponentCloudPolicyStore::ValidatePolicy(
     scoped_ptr<em::PolicyFetchResponse> proto,
     PolicyNamespace* ns,
     em::ExternalPolicyData* payload) {
   em::PolicyData policy_data;
   if (!ValidateProto(
           proto.Pass(), std::string(), std::string(), payload, &policy_data)) {
     return false;
   }
 
@@ skipping 95 matching lines @@
     // If policy for components is ever used for device-level settings then
     // this must support a configurable scope; assuming POLICY_SCOPE_USER is
     // fine for now.
     policy->Set(it.key(), level, POLICY_SCOPE_USER, value.release(), NULL);
   }
 
   return true;
 }
 
 }  // namespace policy