Extract ScopedTestNSSDB from nss_util.

crypto/scoped_test_nss_db.h

+// Copyright 2014 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_SCOPED_TEST_NSS_DB_H_
+#define CRYPTO_SCOPED_TEST_NSS_DB_H_
+
+#include "base/files/scoped_temp_dir.h"
+#include "base/macros.h"
+#include "crypto/crypto_export.h"
+#include "crypto/scoped_nss_types.h"
+
+namespace crypto {
+
+#if defined(USE_NSS)

[Ryan Sleevi, 2014/07/22 01:25:32]

Use source controls to exclude this. Don't #ifdef.

[pneubeck (no reviews), 2014/07/22 14:11:05]

Done. I also added it to a new target crypto_test_support and removed this from
the non-test target 'crypto'.

+// Exposed for tests only.
+// Opens a persistent NSS database in a temporary directory.
+// TODO(mattm): When NSS 3.14 is the minimum version required,
+// switch back to using a separate user DB for each test.
+// Because of https://bugzilla.mozilla.org/show_bug.cgi?id=588269 , the
+// opened user DB is not automatically closed.

[Ryan Sleevi, 2014/07/22 01:25:32]

Update this comment to 3.15.1 (we require 3.14.3, but another bug existed that
wasn't fixed until 3.15.1)

[pneubeck (no reviews), 2014/07/22 06:23:27]

Actually, I'm not sure that I understand the part
  'switch back to using a separate user DB for each test'
correctly.
Do you have a bit more context about what Matt could have meant?
If a test is using this Scoped*DB in several test cases (or the fixture), this
should already either open multiple DBs (if the previous is not closed) or close
the old, delete the tempdir, and create a new DB.
How can it be more 'separate'?

[Ryan Sleevi, 2014/07/22 08:35:09]

Followed-up offline, but for posterity:

Prior to NSS 3.14.3, we opened once and only one, and never closed.
We changed that with NSS 3.15, and discovered a new bug with closing that was
fixed in NSS 3.15.1. We still left it to always-open though (and just leaks).

With NSS 3.15.1+, we can open & close. But we still require NSS 3.14.3+ (due to
being the lowest common denominator across all OS's the last time we bumped NSS
revs)

If the Chrome Linux system versions have been updated, or distros have
consistent newer versions of NSS in their repos (around 8 weeks ago they
didn't), we can bump this rev higher, to make it easier. That's mostly a
research activity (find all documented first class Linux OS's, check their
package repos for (main+security), confirm it's stable)

[pneubeck (no reviews), 2014/07/22 14:11:05]

This comment didn't apply anymore.
Updated the comment to the remaining relevant NSS bug (which matches now the
comment in the .cc).

On 2014/07/22 08:35:09, Ryan Sleevi wrote:

+class CRYPTO_EXPORT_PRIVATE ScopedTestNSSDB {
+ public:
+  ScopedTestNSSDB();
+  ~ScopedTestNSSDB();
+
+  bool is_open() { return slot_; }
+  PK11SlotInfo* slot() { return slot_.get(); }
+
+ private:
+  base::ScopedTempDir temp_dir_;
+  ScopedPK11Slot slot_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedTestNSSDB);
+};
+#endif
+
+}  // namespace crypto
+
+#endif  // CRYPTO_SCOPED_TEST_NSS_DB_H_