Changed previews component to be a layered component.

components/previews/previews_data_savings.h

-// 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.
-
-#ifndef CHROME_BROWSER_PREVIEWS_PREVIEWS_DATA_SAVINGS_H_
-#define CHROME_BROWSER_PREVIEWS_PREVIEWS_DATA_SAVINGS_H_
-
-#include <stdint.h>
-
-#include <string>
-
-#include "base/macros.h"
-#include "base/threading/thread_checker.h"
-
-namespace data_reduction_proxy {
-class DataSavingsRecorder;
-}
-
-namespace previews {
-
-// Provides an interface for previews to report data savings.
-class PreviewsDataSavings {
- public:
-  // Embedder must guarantee that |data_savings_recorder| and
-  // |data_reduction_proxy_settings| outlive this instance.
-  PreviewsDataSavings(
-      data_reduction_proxy::DataSavingsRecorder* data_savings_recorder);
-  ~PreviewsDataSavings();
-
-  // Records the amount of data used by the preview, and the amount of data
-  // that would have been used if the original page had been loaded instead of
-  // the preview. |fully_qualified_domain_name| is the full host name to
-  // attribute the data savings to (e.g., codereview.chromium.org).
-  void RecordDataSavings(const std::string& fully_qualified_domain_name,
-                         int64_t data_used,
-                         int64_t original_size);
-
- private:
-  // Owned by the embedder, must be valid for the lifetime of |this|.
-  // Provides a method to record data savings.
-  data_reduction_proxy::DataSavingsRecorder* data_savings_recorder_;
-
-  // Enforce usage on the UI thread.
-  base::ThreadChecker thread_checker_;
-
-  DISALLOW_COPY_AND_ASSIGN(PreviewsDataSavings);
-};
-
-}  // namespace previews
-
-#endif  // CHROME_BROWSER_PREVIEWS_PREVIEWS_DATA_SAVINGS_H_