Break cyclic dependency between CertDatabase and NSSCertDatabase.

net/cert/cert_database.h

 // Copyright (c) 2012 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 NET_CERT_CERT_DATABASE_H_
 #define NET_CERT_CERT_DATABASE_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "net/base/net_export.h"
 #include "net/cert/x509_certificate.h"
 
 template <typename T> struct DefaultSingletonTraits;
 template <class ObserverType> class ObserverListThreadSafe;
 
 namespace net {
 
-class NSSCertDatabase;
-
 // This class provides cross-platform functions to verify and add user
 // certificates, and to observe changes to the underlying certificate stores.
 
 // TODO(gauravsh): This class could be augmented with methods
 // for all operations that manipulate the underlying system
 // certificate store.
 
 class NET_EXPORT CertDatabase {
  public:
   // A CertDatabase::Observer will be notified on certificate database changes.
@@ skipping 56 matching lines @@
   // the KeyStore used for client certificates, notifies the observers as if a
   // new client certificate was added.
   void OnAndroidKeyStoreChanged();
 
   // On Android, the system database is used. When the system notifies the
   // application that the certificates changed, the observers must be notified.
   void OnAndroidKeyChainChanged();
 #endif
 
 #if defined(USE_NSS)
-  // Observe events from the |source| and forward them to observers of this
-  // CertDatabase.
-  void ObserveNSSCertDatabase(NSSCertDatabase* source);
+  // Returns an Observer which can be used to forward certificate events from
+  // another certificate database (currently NSSCertDatabase) to this database.
+  // Any On* method call on the observer triggers the same event on all
+  // observers of this database. The Observer is owned by this database.
+  Observer* GetObserver();
 #endif
 
  private:
   friend struct DefaultSingletonTraits<CertDatabase>;
 
   CertDatabase();
   ~CertDatabase();
 
   // Broadcasts notifications to all registered observers.
   void NotifyObserversOfCertAdded(const X509Certificate* cert);
   void NotifyObserversOfCertRemoved(const X509Certificate* cert);
   void NotifyObserversOfCACertChanged(const X509Certificate* cert);
 
   const scoped_refptr<ObserverListThreadSafe<Observer> > observer_list_;
 
 #if defined(USE_NSS) || (defined(OS_MACOSX) && !defined(OS_IOS))
   class Notifier;
   friend class Notifier;
   scoped_ptr<Notifier> notifier_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(CertDatabase);
 };
 
 }  // namespace net
 
 #endif  // NET_CERT_CERT_DATABASE_H_