Introduced a ForwardingPolicyProvider.

chrome/browser/policy/forwarding_policy_provider.h

+// 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.
+
+#ifndef CHROME_BROWSER_POLICY_FORWARDING_POLICY_PROVIDER_H_
+#define CHROME_BROWSER_POLICY_FORWARDING_POLICY_PROVIDER_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "chrome/browser/policy/configuration_policy_provider.h"
+#include "components/policy/core/common/policy_namespace.h"
+
+namespace policy {
+
+// A policy provider that forwards calls to another provider.
+// This provider also tracks the SchemaRegistry, and becomes ready after making
+// sure the delegate provider has refreshed its policies with an updated view
+// of the complete schema. It is expected that the delegate's SchemaRegistry
+// is a CombinedSchemaRegistry tracking the forwarding provider's registry.
+class ForwardingPolicyProvider : public ConfigurationPolicyProvider,
+                                 public ConfigurationPolicyProvider::Observer {
+ public:
+  // The |delegate| must outlive this provider.
+  explicit ForwardingPolicyProvider(ConfigurationPolicyProvider* delegate);
+  virtual ~ForwardingPolicyProvider();
+
+  // ConfigurationPolicyProvider:
+  // Note that Init(), Shutdown(), OnSchemaRegistryUpdated() and

[bartfab (slow), 2013/11/11 14:40:08]

I think it would be clearer to list the calls that *are* forwarded to the
|delegate_|: RefreshPolicies() and IsInitializationComplete() for the Chrome
domain.

[Joao da Silva, 2013/11/12 15:26:33]

Done.

+  // OnSchemaRegistryReady() are not forwarded to the |delegate_|.
+  virtual void Init(SchemaRegistry* registry) OVERRIDE;
+  virtual bool IsInitializationComplete(PolicyDomain domain) const OVERRIDE;
+  virtual void RefreshPolicies() OVERRIDE;
+  virtual void OnSchemaRegistryReady() OVERRIDE;
+  virtual void OnSchemaRegistryUpdated(bool has_new_schemas) OVERRIDE;
+
+  // ConfigurationPolicyProvider::Observer:
+  virtual void OnUpdatePolicy(ConfigurationPolicyProvider* provider) OVERRIDE;
+
+ private:
+  enum InitializationState {
+    WAITING_FOR_REGISTRY_READY,
+    WAITING_FOR_REFRESH,
+    READY,
+  };
+
+  ConfigurationPolicyProvider* delegate_;
+  InitializationState state_;
+
+  DISALLOW_COPY_AND_ASSIGN(ForwardingPolicyProvider);
+};
+
+}  // namespace policy
+
+#endif  // CHROME_BROWSER_POLICY_FORWARDING_POLICY_PROVIDER_H_