Remove redundant definition of Spatializer abstract class

third_party/WebKit/Source/platform/audio/Spatializer.cpp

-// 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.
-
-#include "platform/audio/Spatializer.h"
-#include "platform/audio/StereoPanner.h"
-#include "wtf/PtrUtil.h"
-#include <memory>
-
-namespace blink {
-
-std::unique_ptr<Spatializer> Spatializer::create(PanningModel model, float sampleRate)
-{
-    switch (model) {
-    case PanningModelEqualPower:
-        return wrapUnique(new StereoPanner(sampleRate));
-    default:
-        ASSERT_NOT_REACHED();
-        return nullptr;
-    }
-}
-
-Spatializer::~Spatializer()
-{
-}
-
-} // namespace blink
-