Make crypto::GetSystemNSSKeySlot asynchronous.

crypto/nss_util_internal.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 CRYPTO_NSS_UTIL_INTERNAL_H_
 #define CRYPTO_NSS_UTIL_INTERNAL_H_
 
 #include <secmodt.h>
 
 #include "base/callback.h"
@@ skipping 29 matching lines @@
  public:
   AutoSECMODListReadLock();
   ~AutoSECMODListReadLock();
 
  private:
   SECMODListLock* lock_;
   DISALLOW_COPY_AND_ASSIGN(AutoSECMODListReadLock);
 };
 
 #if defined(OS_CHROMEOS)
-// Returns a reference to the system-wide TPM slot. Caller must release returned
-// reference with PK11_FreeSlot.
-CRYPTO_EXPORT PK11SlotInfo* GetSystemNSSKeySlot() WARN_UNUSED_RESULT;
+// Returns a reference to the system-wide TPM slot if it is loaded. If it is not
+// loaded and |callback| is non-null, the |callback| will be run once the slot
+// is loaded.
+CRYPTO_EXPORT ScopedPK11Slot GetSystemNSSKeySlot(
+    const base::Callback<void(ScopedPK11Slot)>& callback) WARN_UNUSED_RESULT;
 
 // Sets the test system slot. If this was called before
 // InitializeTPMTokenAndSystemSlot and no system token is provided by the Chaps
 // module, then this test slot will be used and the initialization continues as
 // if Chaps had provided this test slot. In particular, |slot| will be exposed
 // by |GetSystemNSSKeySlot| and |IsTPMTokenReady| will return true.
 // This must must not be called consecutively with a |slot| != NULL. If |slot|
 // is NULL, the test system slot is unset.
 CRYPTO_EXPORT_PRIVATE void SetSystemKeySlotForTesting(ScopedPK11Slot slot);
 
@@ skipping 41 matching lines @@
 
 // Closes the NSS DB for |username_hash| that was previously opened by the
 // *Initialize*ForChromeOSUser functions.
 CRYPTO_EXPORT_PRIVATE void CloseChromeOSUserForTesting(
     const std::string& username_hash);
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace crypto
 
 #endif  // CRYPTO_NSS_UTIL_INTERNAL_H_