Use std::unique_ptr<> for WebTaskRunner::clone

third_party/WebKit/Source/platform/TimerTest.cpp

 // Copyright 2015 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 "platform/Timer.h"
 
 #include "platform/testing/TestingPlatformSupport.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebScheduler.h"
 #include "public/platform/WebThread.h"
@@ skipping 76 matching lines @@
     {
         m_timerTasks->push(DelayedTask(task, delayMs * 0.001));
     }
 
     bool runsTasksOnCurrentThread() override
     {
         NOTREACHED();
         return true;
     }
 
-    WebTaskRunner* clone() override
+    std::unique_ptr<WebTaskRunner> clone() override
     {
         NOTREACHED();
         return nullptr;
     }
 
     double virtualTimeSeconds() const override
     {
         NOTREACHED();
         return 0.0;
     }
@@ skipping 676 matching lines @@
     TimerForTest<TimerTest> timer(this, &TimerTest::countingTask, &taskRunner);
     timer.startOneShot(0, BLINK_FROM_HERE);
 
     // Make sure the task was posted on taskRunner.
     EXPECT_FALSE(timerTasks.empty());
 }
 
 
 } // namespace
 } // namespace blink