Add a Clock and TickClock interface for mocking out time

base/time/default_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/message_loop_proxy.h"
-
-#include "base/bind.h"
+#include "base/time/default_tick_clock.h"
 
 namespace base {
 
-MessageLoopProxy::MessageLoopProxy() {
-}
+DefaultTickClock::~DefaultTickClock() {}
 
-MessageLoopProxy::~MessageLoopProxy() {
+TimeTicks DefaultTickClock::NowTicks() {
+  return TimeTicks::Now();
 }
 
 }  // namespace base