Linux: add a Credentials class to handle Linux capabilities.

sandbox/linux/services/credentials_unittest.cc

+// 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.
+
+#include "sandbox/linux/services/credentials.h"
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "sandbox/linux/tests/unit_tests.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+
+// Give dynamic tools a simple thing to test.
+TEST(Credentials, CreateAndDestroy) {
+  {
+    Credentials cred1;
+    (void) cred1;
+  }
+  scoped_ptr<Credentials> cred2(new Credentials);
+}
+
+SANDBOX_TEST(Credentials, DropAllCaps) {
+  Credentials creds;
+  creds.DropAllCapabilities();
+  SANDBOX_ASSERT(!creds.HasAnyCapability());
+}
+
+SANDBOX_TEST(Credentials, GetCurrentCapString) {
+  Credentials creds;
+  creds.DropAllCapabilities();
+  const char kNoCapabilityText[] = "=";
+  SANDBOX_ASSERT(*creds.GetCurrentCapString() == kNoCapabilityText);
+}
+
+}  // namespace sandbox.