Extract nested and private classes from VideoCaptureBufferPool

content/browser/renderer_host/media/video_capture_buffer_tracker_factory.cc

+// Copyright 2016 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 "content/browser/renderer_host/media/video_capture_buffer_tracker_factory.h"
+
+#include "base/memory/ptr_util.h"
+
+#include "content/browser/renderer_host/media/gpu_memory_buffer_tracker.h"
+#include "content/browser/renderer_host/media/shared_memory_buffer_tracker.h"
+
+namespace content {
+
+// static
+std::unique_ptr<VideoCaptureBufferTracker>
+VideoCaptureBufferTrackerFactory::CreateTracker(
+    media::VideoPixelStorage storage) {
+  switch (storage) {
+    case media::PIXEL_STORAGE_GPUMEMORYBUFFER:
+      return base::MakeUnique<GpuMemoryBufferTracker>();
+    case media::PIXEL_STORAGE_CPU:
+      return base::MakeUnique<SharedMemoryBufferTracker>();
+  }
+  NOTREACHED();
+  return std::unique_ptr<VideoCaptureBufferTracker>();
+}
+
+}  // namespace content