Move tracing_impl code to mojo/common

sky/viewer/services/tracing_impl.h

-// Copyright 2014 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.
-
-#ifndef SKY_VIEWER_SERVICES_TRACING_IMPL_H_
-#define SKY_VIEWER_SERVICES_TRACING_IMPL_H_
-
-#include "base/basictypes.h"
-#include "mojo/public/cpp/application/interface_factory_impl.h"
-#include "sky/viewer/services/tracing.mojom.h"
-
-namespace sky {
-
-class TracingImpl : public mojo::InterfaceImpl<Tracing> {
- public:
-  TracingImpl();
-  virtual ~TracingImpl();
-
- private:
-  // Overridden from Tracing:
-  void Start() override;
-  void Stop() override;
-
-  DISALLOW_COPY_AND_ASSIGN(TracingImpl);
-};
-
-typedef mojo::InterfaceFactoryImpl<TracingImpl> TracingFactory;
-
-}  // namespace sky
-
-#endif  // SKY_VIEWER_SERVICES_TRACING_IMPL_H_