Add a Clock and TickClock interface for mocking out time

base/test/simple_test_tick_clock.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 "base/test/simple_test_tick_clock.h"
+
+namespace base {
+
+SimpleTestTickClock::SimpleTestTickClock() {}
+
+SimpleTestTickClock::~SimpleTestTickClock() {}
+
+TimeTicks SimpleTestTickClock::NowTicks() {
+  AutoLock lock(lock_);
+  return now_ticks_;
+}
+
+void SimpleTestTickClock::Advance(TimeDelta delta) {
+  AutoLock lock(lock_);
+  now_ticks_ += delta;

[jar (doing other things), 2012/12/17 20:29:21]

nit: consider DCHECK_GE(delta, TimeDelta());

[akalin, 2012/12/17 22:38:31]

Done.  Although it has to be DCHECK( >= ) since TimeDelta doesn't overload <<.

+}
+
+}  // namespace base