Refactor ScrollAnimatorMac to use CancellableTaskFactory

third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 109 matching lines @@
         m_tasks->append(adoptPtr(task));
     }
 
     void postDelayedTask(const WebTraceLocation&, Task*, double delayMs) override
     {
         ASSERT_NOT_REACHED();
     }
 
     WebTaskRunner* clone() override
     {
-        ASSERT_NOT_REACHED();
-        return nullptr;
+        return new TestingPlatformMockWebTaskRunner(m_tasks);
     }
 
 private:
     Deque<OwnPtr<WebTaskRunner::Task>>* m_tasks; // NOT OWNED
 };
 
 // TestingPlatformMockScheduler definition:
 
 TestingPlatformMockScheduler::TestingPlatformMockScheduler()
     : m_mockWebTaskRunner(adoptPtr(new TestingPlatformMockWebTaskRunner(&m_tasks))) { }
@@ skipping 69 matching lines @@
 {
     return m_mockWebThread.get();
 }
 
 TestingPlatformMockScheduler* TestingPlatformSupportWithMockScheduler::mockWebScheduler()
 {
     return m_mockWebThread->mockWebScheduler();
 }
 
 } // namespace blink