Decoupled the SchemaRegistryService from SchemaRegistry.

The service is not a SchemaRegistry anymore but owns one instead. This
enables the service to own subclasses of SchemaRegistry.

Also added a ForwardingSchemaRegisy, which wraps another
SchemaRegistry. This will be used in a future CL.

R=bartfab@chromium.org
TBR=kalman@chromium.org
BUG=224596

Review URL: https://codereview.chromium.org/349643002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278735 0039d316-1c4b-4281-b951-d872f2087c98

12 files changed, 236 insertions, 81 deletions

diff --git a/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc b/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc
index ba317a7..6b0e11c 100644
--- a/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc
+++ b/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc
@@ -209,7 +209,8 @@ scoped_ptr<UserCloudPolicyManagerChromeOS>
     manager->EnableWildcardLoginCheck(username);
   }
 
-  manager->Init(SchemaRegistryServiceFactory::GetForContext(profile));
+  manager->Init(
+      SchemaRegistryServiceFactory::GetForContext(profile)->registry());
   manager->Connect(g_browser_process->local_state(),
                    device_management_service,
                    g_browser_process->system_request_context(),
diff --git a/chrome/browser/extensions/api/storage/managed_value_store_cache.cc b/chrome/browser/extensions/api/storage/managed_value_store_cache.cc
index 92451c4..75387a9 100644
--- a/chrome/browser/extensions/api/storage/managed_value_store_cache.cc
+++ b/chrome/browser/extensions/api/storage/managed_value_store_cache.cc
@@ -107,8 +107,8 @@ class ManagedValueStoreCache::ExtensionTracker
 ManagedValueStoreCache::ExtensionTracker::ExtensionTracker(Profile* profile)
     : profile_(profile),
       extension_registry_observer_(this),
-      schema_registry_(
-          policy::SchemaRegistryServiceFactory::GetForContext(profile)),
+      schema_registry_(policy::SchemaRegistryServiceFactory::GetForContext(
+                           profile)->registry()),
       weak_factory_(this) {
   extension_registry_observer_.Add(ExtensionRegistry::Get(profile_));
   // Load schemas when the extension system is ready. It might be ready now.
@@ -291,7 +291,7 @@ void ManagedValueStoreCache::OnPolicyServiceInitialized(
   // The PolicyService now has all the initial policies ready. Send policy
   // for all the managed extensions to their backing stores now.
   policy::SchemaRegistry* registry =
-      policy::SchemaRegistryServiceFactory::GetForContext(profile_);
+      policy::SchemaRegistryServiceFactory::GetForContext(profile_)->registry();
   const policy::ComponentMap* map = registry->schema_map()->GetComponents(
       policy::POLICY_DOMAIN_EXTENSIONS);
   if (!map)
diff --git a/chrome/browser/extensions/api/storage/settings_apitest.cc b/chrome/browser/extensions/api/storage/settings_apitest.cc
index 7efa0c1..98a36fc 100644
--- a/chrome/browser/extensions/api/storage/settings_apitest.cc
+++ b/chrome/browser/extensions/api/storage/settings_apitest.cc
@@ -432,7 +432,7 @@ IN_PROC_BROWSER_TEST_F(ExtensionSettingsApiTest, ExtensionsSchemas) {
   message_.clear();
 
   policy::SchemaRegistry* registry =
-      policy::SchemaRegistryServiceFactory::GetForContext(profile);
+      policy::SchemaRegistryServiceFactory::GetForContext(profile)->registry();
   ASSERT_TRUE(registry);
   EXPECT_FALSE(registry->schema_map()->GetSchema(policy::PolicyNamespace(
       policy::POLICY_DOMAIN_EXTENSIONS, kManagedStorageExtensionId)));
diff --git a/chrome/browser/policy/cloud/user_cloud_policy_manager_factory.cc b/chrome/browser/policy/cloud/user_cloud_policy_manager_factory.cc
index 3f43c4b..f1e5c35 100644
--- a/chrome/browser/policy/cloud/user_cloud_policy_manager_factory.cc
+++ b/chrome/browser/policy/cloud/user_cloud_policy_manager_factory.cc
@@ -160,7 +160,8 @@ UserCloudPolicyManagerFactory::CreateManagerForOriginalBrowserContext(
       base::MessageLoopProxy::current(),
       file_task_runner,
       io_task_runner));
-  manager->Init(SchemaRegistryServiceFactory::GetForContext(context));
+  manager->Init(
+      SchemaRegistryServiceFactory::GetForContext(context)->registry());
   manager_wrappers_[context] = new ManagerWrapper(manager.get());
   return manager.Pass();
 }
diff --git a/chrome/browser/policy/profile_policy_connector_factory.cc b/chrome/browser/policy/profile_policy_connector_factory.cc
index 8089a3d..5f21949 100644
--- a/chrome/browser/policy/profile_policy_connector_factory.cc
+++ b/chrome/browser/policy/profile_policy_connector_factory.cc
@@ -91,7 +91,8 @@ ProfilePolicyConnectorFactory::CreateForProfileInternal(
   CloudPolicyManager* user_cloud_policy_manager = NULL;
 
 #if defined(ENABLE_CONFIGURATION_POLICY)
-  schema_registry = SchemaRegistryServiceFactory::GetForContext(profile);
+  schema_registry =
+      SchemaRegistryServiceFactory::GetForContext(profile)->registry();
 
 #if defined(OS_CHROMEOS)
   chromeos::User* user = NULL;
diff --git a/chrome/browser/policy/schema_registry_service.cc b/chrome/browser/policy/schema_registry_service.cc
index b8124cd..9cf2b49 100644
--- a/chrome/browser/policy/schema_registry_service.cc
+++ b/chrome/browser/policy/schema_registry_service.cc
@@ -4,31 +4,26 @@
 
 #include "chrome/browser/policy/schema_registry_service.h"
 
-#include "base/logging.h"
 #include "components/policy/core/common/policy_namespace.h"
 #include "components/policy/core/common/schema.h"
+#include "components/policy/core/common/schema_registry.h"
 
 namespace policy {
 
 SchemaRegistryService::SchemaRegistryService(
+    scoped_ptr<SchemaRegistry> registry,
     const Schema& chrome_schema,
     CombinedSchemaRegistry* global_registry)
-    : global_registry_(global_registry) {
-  if (chrome_schema.valid())
-    RegisterComponent(PolicyNamespace(POLICY_DOMAIN_CHROME, ""), chrome_schema);
-  SetReady(POLICY_DOMAIN_CHROME);
-  if (global_registry_)
-    global_registry->Track(this);
+    : registry_(registry.Pass()) {
+  if (chrome_schema.valid()) {
+    registry_->RegisterComponent(PolicyNamespace(POLICY_DOMAIN_CHROME, ""),
+                                 chrome_schema);
+  }
+  registry_->SetReady(POLICY_DOMAIN_CHROME);
+  if (global_registry)
+    global_registry->Track(registry_.get());
 }
 
 SchemaRegistryService::~SchemaRegistryService() {}
 
-void SchemaRegistryService::Shutdown() {
-  if (global_registry_) {
-    global_registry_->Untrack(this);
-    global_registry_ = NULL;
-  }
-  DCHECK(!HasObservers());
-}
-
 }  // namespace policy
diff --git a/chrome/browser/policy/schema_registry_service.h b/chrome/browser/policy/schema_registry_service.h
index ecf97d7..24beefc 100644
--- a/chrome/browser/policy/schema_registry_service.h
+++ b/chrome/browser/policy/schema_registry_service.h
@@ -6,30 +6,30 @@
 #define CHROME_BROWSER_POLICY_SCHEMA_REGISTRY_SERVICE_H_
 
 #include "base/basictypes.h"
-#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "components/keyed_service/core/keyed_service.h"
-#include "components/policy/core/common/schema_registry.h"
 
 namespace policy {
 
+class CombinedSchemaRegistry;
 class Schema;
+class SchemaRegistry;
 
-// A SchemaRegistry that is also a KeyedService, and is associated
-// with a Profile.
-class SchemaRegistryService : public SchemaRegistry, public KeyedService {
+// A KeyedService associated with a Profile that contains a SchemaRegistry.
+class SchemaRegistryService : public KeyedService {
  public:
-  // This SchemaRegistry will initially contain only the |chrome_schema|, if
+  // This |registry| will initially contain only the |chrome_schema|, if
   // it's valid. The optional |global_registry| must outlive this, and will
-  // track this registry.
-  SchemaRegistryService(const Schema& chrome_schema,
+  // track |registry|.
+  SchemaRegistryService(scoped_ptr<SchemaRegistry> registry,
+                        const Schema& chrome_schema,
                         CombinedSchemaRegistry* global_registry);
   virtual ~SchemaRegistryService();
 
-  // KeyedService:
-  virtual void Shutdown() OVERRIDE;
+  SchemaRegistry* registry() const { return registry_.get(); }
 
  private:
-  CombinedSchemaRegistry* global_registry_;
+  scoped_ptr<SchemaRegistry> registry_;
 
   DISALLOW_COPY_AND_ASSIGN(SchemaRegistryService);
 };
diff --git a/chrome/browser/policy/schema_registry_service_factory.cc b/chrome/browser/policy/schema_registry_service_factory.cc
index 71758ff..eaa5268 100644
--- a/chrome/browser/policy/schema_registry_service_factory.cc
+++ b/chrome/browser/policy/schema_registry_service_factory.cc
@@ -60,10 +60,11 @@ SchemaRegistryServiceFactory::CreateForContextInternal(
     CombinedSchemaRegistry* global_registry) {
   DCHECK(!context->IsOffTheRecord());
   DCHECK(registries_.find(context) == registries_.end());
-  SchemaRegistryService* registry =
-      new SchemaRegistryService(chrome_schema, global_registry);
-  registries_[context] = registry;
-  return make_scoped_ptr(registry);
+  scoped_ptr<SchemaRegistry> registry(new SchemaRegistry);
+  scoped_ptr<SchemaRegistryService> service(new SchemaRegistryService(
+      registry.Pass(), chrome_schema, global_registry));
+  registries_[context] = service.get();
+  return service.Pass();
 }
 
 void SchemaRegistryServiceFactory::BrowserContextShutdown(
diff --git a/chrome/browser/ui/webui/policy_ui.cc b/chrome/browser/ui/webui/policy_ui.cc
index 15c0b98..b1f3c39 100644
--- a/chrome/browser/ui/webui/policy_ui.cc
+++ b/chrome/browser/ui/webui/policy_ui.cc
@@ -613,7 +613,7 @@ void PolicyUIHandler::SendPolicyNames() const {
   Profile* profile = Profile::FromWebUI(web_ui());
   policy::SchemaRegistry* registry =
       policy::SchemaRegistryServiceFactory::GetForContext(
-          profile->GetOriginalProfile());
+          profile->GetOriginalProfile())->registry();
   scoped_refptr<policy::SchemaMap> schema_map = registry->schema_map();
 
   // Add Chrome policy names.
diff --git a/components/policy/core/common/schema_registry.cc b/components/policy/core/common/schema_registry.cc
index ff95579..f3cb0ed 100644
--- a/components/policy/core/common/schema_registry.cc
+++ b/components/policy/core/common/schema_registry.cc
@@ -10,6 +10,8 @@ namespace policy {
 
 SchemaRegistry::Observer::~Observer() {}
 
+SchemaRegistry::InternalObserver::~InternalObserver() {}
+
 SchemaRegistry::SchemaRegistry() : schema_map_(new SchemaMap) {
   for (int i = 0; i < POLICY_DOMAIN_SIZE; ++i)
     domains_ready_[i] = false;
@@ -18,7 +20,11 @@ SchemaRegistry::SchemaRegistry() : schema_map_(new SchemaMap) {
 #endif
 }
 
-SchemaRegistry::~SchemaRegistry() {}
+SchemaRegistry::~SchemaRegistry() {
+  FOR_EACH_OBSERVER(InternalObserver,
+                    internal_observers_,
+                    OnSchemaRegistryShuttingDown(this));
+}
 
 void SchemaRegistry::RegisterComponent(const PolicyNamespace& ns,
                                        const Schema& schema) {
@@ -77,15 +83,19 @@ void SchemaRegistry::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
+void SchemaRegistry::AddInternalObserver(InternalObserver* observer) {
+  internal_observers_.AddObserver(observer);
+}
+
+void SchemaRegistry::RemoveInternalObserver(InternalObserver* observer) {
+  internal_observers_.RemoveObserver(observer);
+}
+
 void SchemaRegistry::Notify(bool has_new_schemas) {
   FOR_EACH_OBSERVER(
       Observer, observers_, OnSchemaRegistryUpdated(has_new_schemas));
 }
 
-bool SchemaRegistry::HasObservers() const {
-  return observers_.might_have_observers();
-}
-
 CombinedSchemaRegistry::CombinedSchemaRegistry()
     : own_schema_map_(new SchemaMap) {
   // The combined registry is always ready, since it can always start tracking
@@ -100,22 +110,13 @@ CombinedSchemaRegistry::~CombinedSchemaRegistry() {}
 void CombinedSchemaRegistry::Track(SchemaRegistry* registry) {
   registries_.insert(registry);
   registry->AddObserver(this);
+  registry->AddInternalObserver(this);
   // Recombine the maps only if the |registry| has any components other than
   // POLICY_DOMAIN_CHROME.
   if (registry->schema_map()->HasComponents())
     Combine(true);
 }
 
-void CombinedSchemaRegistry::Untrack(SchemaRegistry* registry) {
-  registry->RemoveObserver(this);
-  if (registries_.erase(registry) != 0) {
-    if (registry->schema_map()->HasComponents())
-      Combine(false);
-  } else {
-    NOTREACHED();
-  }
-}
-
 void CombinedSchemaRegistry::RegisterComponents(
     PolicyDomain domain,
     const ComponentMap& components) {
@@ -146,6 +147,18 @@ void CombinedSchemaRegistry::OnSchemaRegistryReady() {
   // Ignore.
 }
 
+void CombinedSchemaRegistry::OnSchemaRegistryShuttingDown(
+    SchemaRegistry* registry) {
+  registry->RemoveObserver(this);
+  registry->RemoveInternalObserver(this);
+  if (registries_.erase(registry) != 0) {
+    if (registry->schema_map()->HasComponents())
+      Combine(false);
+  } else {
+    NOTREACHED();
+  }
+}
+
 void CombinedSchemaRegistry::Combine(bool has_new_schemas) {
   // If two registries publish a Schema for the same component then it's
   // undefined which version gets in the combined registry.
@@ -175,4 +188,53 @@ void CombinedSchemaRegistry::Combine(bool has_new_schemas) {
   Notify(has_new_schemas);
 }
 
+ForwardingSchemaRegistry::ForwardingSchemaRegistry(SchemaRegistry* wrapped)
+    : wrapped_(wrapped) {
+  schema_map_ = wrapped_->schema_map();
+  wrapped_->AddObserver(this);
+  wrapped_->AddInternalObserver(this);
+  // This registry is always ready.
+  for (int i = 0; i < POLICY_DOMAIN_SIZE; ++i)
+    SetReady(static_cast<PolicyDomain>(i));
+}
+
+ForwardingSchemaRegistry::~ForwardingSchemaRegistry() {
+  if (wrapped_) {
+    wrapped_->RemoveObserver(this);
+    wrapped_->RemoveInternalObserver(this);
+  }
+}
+
+void ForwardingSchemaRegistry::RegisterComponents(
+    PolicyDomain domain,
+    const ComponentMap& components) {
+  if (wrapped_)
+    wrapped_->RegisterComponents(domain, components);
+  // Ignore otherwise.
+}
+
+void ForwardingSchemaRegistry::UnregisterComponent(const PolicyNamespace& ns) {
+  if (wrapped_)
+    wrapped_->UnregisterComponent(ns);
+  // Ignore otherwise.
+}
+
+void ForwardingSchemaRegistry::OnSchemaRegistryUpdated(bool has_new_schemas) {
+  schema_map_ = wrapped_->schema_map();
+  Notify(has_new_schemas);
+}
+
+void ForwardingSchemaRegistry::OnSchemaRegistryReady() {
+  // Ignore.
+}
+
+void ForwardingSchemaRegistry::OnSchemaRegistryShuttingDown(
+    SchemaRegistry* registry) {
+  DCHECK_EQ(wrapped_, registry);
+  wrapped_->RemoveObserver(this);
+  wrapped_->RemoveInternalObserver(this);
+  wrapped_ = NULL;
+  // Keep serving the same |schema_map_|.
+}
+
 }  // namespace policy
diff --git a/components/policy/core/common/schema_registry.h b/components/policy/core/common/schema_registry.h
index b9f7fa8..6df4db2 100644
--- a/components/policy/core/common/schema_registry.h
+++ b/components/policy/core/common/schema_registry.h
@@ -43,6 +43,16 @@ class POLICY_EXPORT SchemaRegistry : public base::NonThreadSafe {
     virtual ~Observer();
   };
 
+  // This observer is only meant to be used by subclasses.
+  class POLICY_EXPORT InternalObserver {
+   public:
+    // Invoked when |registry| is about to be destroyed.
+    virtual void OnSchemaRegistryShuttingDown(SchemaRegistry* registry) = 0;
+
+   protected:
+    virtual ~InternalObserver();
+  };
+
   SchemaRegistry();
   virtual ~SchemaRegistry();
 
@@ -69,7 +79,8 @@ class POLICY_EXPORT SchemaRegistry : public base::NonThreadSafe {
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
-  bool HasObservers() const;
+  void AddInternalObserver(InternalObserver* observer);
+  void RemoveInternalObserver(InternalObserver* observer);
 
  protected:
   void Notify(bool has_new_schemas);
@@ -78,30 +89,35 @@ class POLICY_EXPORT SchemaRegistry : public base::NonThreadSafe {
 
  private:
   ObserverList<Observer, true> observers_;
+  ObserverList<InternalObserver, true> internal_observers_;
   bool domains_ready_[POLICY_DOMAIN_SIZE];
 
   DISALLOW_COPY_AND_ASSIGN(SchemaRegistry);
 };
 
 // A registry that combines the maps of other registries.
-class POLICY_EXPORT CombinedSchemaRegistry : public SchemaRegistry,
-                                             public SchemaRegistry::Observer {
+class POLICY_EXPORT CombinedSchemaRegistry
+    : public SchemaRegistry,
+      public SchemaRegistry::Observer,
+      public SchemaRegistry::InternalObserver {
  public:
   CombinedSchemaRegistry();
   virtual ~CombinedSchemaRegistry();
 
   void Track(SchemaRegistry* registry);
-  void Untrack(SchemaRegistry* registry);
 
+  // SchemaRegistry:
   virtual void RegisterComponents(PolicyDomain domain,
                                   const ComponentMap& components) OVERRIDE;
-
   virtual void UnregisterComponent(const PolicyNamespace& ns) OVERRIDE;
 
+  // SchemaRegistry::Observer:
   virtual void OnSchemaRegistryUpdated(bool has_new_schemas) OVERRIDE;
-
   virtual void OnSchemaRegistryReady() OVERRIDE;
 
+  // SchemaRegistry::InternalObserver:
+  virtual void OnSchemaRegistryShuttingDown(SchemaRegistry* registry) OVERRIDE;
+
  private:
   void Combine(bool has_new_schemas);
 
@@ -111,6 +127,35 @@ class POLICY_EXPORT CombinedSchemaRegistry : public SchemaRegistry,
   DISALLOW_COPY_AND_ASSIGN(CombinedSchemaRegistry);
 };
 
+// A registry that wraps another schema registry.
+class POLICY_EXPORT ForwardingSchemaRegistry
+    : public SchemaRegistry,
+      public SchemaRegistry::Observer,
+      public SchemaRegistry::InternalObserver {
+ public:
+  // This registry will stop updating its SchemaMap when |wrapped| is
+  // destroyed.
+  explicit ForwardingSchemaRegistry(SchemaRegistry* wrapped);
+  virtual ~ForwardingSchemaRegistry();
+
+  // SchemaRegistry:
+  virtual void RegisterComponents(PolicyDomain domain,
+                                  const ComponentMap& components) OVERRIDE;
+  virtual void UnregisterComponent(const PolicyNamespace& ns) OVERRIDE;
+
+  // SchemaRegistry::Observer:
+  virtual void OnSchemaRegistryUpdated(bool has_new_schemas) OVERRIDE;
+  virtual void OnSchemaRegistryReady() OVERRIDE;
+
+  // SchemaRegistry::InternalObserver:
+  virtual void OnSchemaRegistryShuttingDown(SchemaRegistry* registry) OVERRIDE;
+
+ private:
+  SchemaRegistry* wrapped_;
+
+  DISALLOW_COPY_AND_ASSIGN(ForwardingSchemaRegistry);
+};
+
 }  // namespace policy
 
 #endif  // COMPONENTS_POLICY_CORE_COMMON_SCHEMA_REGISTRY_H_
diff --git a/components/policy/core/common/schema_registry_unittest.cc b/components/policy/core/common/schema_registry_unittest.cc
index 36749ea..b3d6dae 100644
--- a/components/policy/core/common/schema_registry_unittest.cc
+++ b/components/policy/core/common/schema_registry_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "components/policy/core/common/schema_registry.h"
 
+#include "base/memory/scoped_ptr.h"
 #include "components/policy/core/common/policy_namespace.h"
 #include "components/policy/core/common/schema.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -48,6 +49,14 @@ class MockSchemaRegistryObserver : public SchemaRegistry::Observer {
   MOCK_METHOD0(OnSchemaRegistryReady, void());
 };
 
+bool SchemaMapEquals(const scoped_refptr<SchemaMap>& schema_map1,
+                     const scoped_refptr<SchemaMap>& schema_map2) {
+  PolicyNamespaceList added;
+  PolicyNamespaceList removed;
+  schema_map1->GetChanges(schema_map2, &removed, &added);
+  return added.empty() && removed.empty();
+}
+
 }  // namespace
 
 TEST(SchemaRegistryTest, Notifications) {
@@ -57,9 +66,7 @@ TEST(SchemaRegistryTest, Notifications) {
 
   MockSchemaRegistryObserver observer;
   SchemaRegistry registry;
-  EXPECT_FALSE(registry.HasObservers());
   registry.AddObserver(&observer);
-  EXPECT_TRUE(registry.HasObservers());
 
   ASSERT_TRUE(registry.schema_map());
   EXPECT_FALSE(registry.schema_map()->GetSchema(
@@ -98,7 +105,6 @@ TEST(SchemaRegistryTest, Notifications) {
   Mock::VerifyAndClearExpectations(&observer);
 
   registry.RemoveObserver(&observer);
-  EXPECT_FALSE(registry.HasObservers());
 }
 
 TEST(SchemaRegistryTest, IsReady) {
@@ -134,25 +140,25 @@ TEST(SchemaRegistryTest, Combined) {
   ASSERT_TRUE(schema.valid()) << error;
 
   MockSchemaRegistryObserver observer;
-  SchemaRegistry registry1;
-  SchemaRegistry registry2;
+  scoped_ptr<SchemaRegistry> registry1(new SchemaRegistry);
+  scoped_ptr<SchemaRegistry> registry2(new SchemaRegistry);
   CombinedSchemaRegistry combined;
   combined.AddObserver(&observer);
 
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(_)).Times(0);
-  registry1.RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "abc"),
-                              schema);
+  registry1->RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "abc"),
+                               schema);
   Mock::VerifyAndClearExpectations(&observer);
 
   // Starting to track a registry issues notifications when it comes with new
   // schemas.
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(true));
-  combined.Track(&registry1);
+  combined.Track(registry1.get());
   Mock::VerifyAndClearExpectations(&observer);
 
   // Adding a new empty registry does not trigger notifications.
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(_)).Times(0);
-  combined.Track(&registry2);
+  combined.Track(registry2.get());
   Mock::VerifyAndClearExpectations(&observer);
 
   // Adding the same component to the combined registry itself triggers
@@ -164,15 +170,15 @@ TEST(SchemaRegistryTest, Combined) {
 
   // Adding components to the sub-registries triggers notifications.
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(true));
-  registry2.RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def"),
-                              schema);
+  registry2->RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def"),
+                               schema);
   Mock::VerifyAndClearExpectations(&observer);
 
   // If the same component is published in 2 sub-registries then the combined
   // registry publishes one of them.
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(true));
-  registry1.RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def"),
-                              schema);
+  registry1->RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def"),
+                               schema);
   Mock::VerifyAndClearExpectations(&observer);
 
   ASSERT_EQ(1u, combined.schema_map()->GetDomains().size());
@@ -188,7 +194,7 @@ TEST(SchemaRegistryTest, Combined) {
       PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "xyz")));
 
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(false));
-  registry1.UnregisterComponent(
+  registry1->UnregisterComponent(
       PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "abc"));
   Mock::VerifyAndClearExpectations(&observer);
   // Still registered at the combined registry.
@@ -204,7 +210,7 @@ TEST(SchemaRegistryTest, Combined) {
       PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "abc")));
 
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(false));
-  registry1.UnregisterComponent(
+  registry1->UnregisterComponent(
       PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def"));
   Mock::VerifyAndClearExpectations(&observer);
   // Still registered at registry2.
@@ -212,7 +218,7 @@ TEST(SchemaRegistryTest, Combined) {
       PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def")));
 
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(false));
-  registry2.UnregisterComponent(
+  registry2->UnregisterComponent(
       PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def"));
   Mock::VerifyAndClearExpectations(&observer);
   // Now it's gone.
@@ -220,23 +226,66 @@ TEST(SchemaRegistryTest, Combined) {
       PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "def")));
 
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(true)).Times(2);
-  registry1.RegisterComponent(PolicyNamespace(POLICY_DOMAIN_CHROME, ""),
-                              schema);
-  registry2.RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "hij"),
-                              schema);
+  registry1->RegisterComponent(PolicyNamespace(POLICY_DOMAIN_CHROME, ""),
+                               schema);
+  registry2->RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "hij"),
+                               schema);
   Mock::VerifyAndClearExpectations(&observer);
 
   // Untracking |registry1| doesn't trigger an update notification, because it
   // doesn't contain any components.
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(_)).Times(0);
-  combined.Untrack(&registry1);
+  registry1.reset();
   Mock::VerifyAndClearExpectations(&observer);
 
   EXPECT_CALL(observer, OnSchemaRegistryUpdated(false));
-  combined.Untrack(&registry2);
+  registry2.reset();
   Mock::VerifyAndClearExpectations(&observer);
 
   combined.RemoveObserver(&observer);
 }
 
+TEST(SchemaRegistryTest, ForwardingSchemaRegistry) {
+  scoped_ptr<SchemaRegistry> registry(new SchemaRegistry);
+  ForwardingSchemaRegistry forwarding(registry.get());
+  MockSchemaRegistryObserver observer;
+  forwarding.AddObserver(&observer);
+
+  EXPECT_FALSE(registry->IsReady());
+  // The ForwardingSchemaRegistry is always ready, even if the wrapped registry
+  // isn't.
+  EXPECT_TRUE(forwarding.IsReady());
+  // But they alreday have the same SchemaMap.
+  EXPECT_TRUE(SchemaMapEquals(registry->schema_map(), forwarding.schema_map()));
+
+  EXPECT_CALL(observer, OnSchemaRegistryUpdated(true));
+  registry->RegisterComponent(PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "abc"),
+                              Schema());
+  Mock::VerifyAndClearExpectations(&observer);
+  EXPECT_TRUE(SchemaMapEquals(registry->schema_map(), forwarding.schema_map()));
+
+  EXPECT_CALL(observer, OnSchemaRegistryUpdated(false));
+  registry->UnregisterComponent(
+      PolicyNamespace(POLICY_DOMAIN_EXTENSIONS, "abc"));
+  Mock::VerifyAndClearExpectations(&observer);
+  EXPECT_TRUE(SchemaMapEquals(registry->schema_map(), forwarding.schema_map()));
+
+  // No notifications expected for this call.
+  EXPECT_FALSE(registry->IsReady());
+  registry->SetReady(POLICY_DOMAIN_CHROME);
+  registry->SetReady(POLICY_DOMAIN_EXTENSIONS);
+  EXPECT_TRUE(registry->IsReady());
+  EXPECT_TRUE(SchemaMapEquals(registry->schema_map(), forwarding.schema_map()));
+  Mock::VerifyAndClearExpectations(&observer);
+
+  // Keep the same SchemaMap when the original registry is gone.
+  // No notifications are expected in this case either.
+  scoped_refptr<SchemaMap> schema_map = registry->schema_map();
+  registry.reset();
+  EXPECT_TRUE(SchemaMapEquals(schema_map, forwarding.schema_map()));
+  Mock::VerifyAndClearExpectations(&observer);
+
+  forwarding.RemoveObserver(&observer);
+}
+
 }  // namespace policy