Make DisplayInfoProvider an interface

chrome/browser/extensions/display_info_provider_mac.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 CHROME_BROWSER_EXTENSIONS_DISPLAY_INFO_PROVIDER_MAC_H_
+#define CHROME_BROWSER_EXTENSIONS_DISPLAY_INFO_PROVIDER_MAC_H_
+
+#include "chrome/browser/extensions/api/system_display/display_info_provider.h"
+
+namespace extensions {
+
+class DisplayInfoProviderMac : public DisplayInfoProvider {
+ public:
+  DisplayInfoProviderMac();
+  virtual ~DisplayInfoProviderMac();
+
+  // DisplayInfoProvider implementation.
+  virtual bool SetInfo(const std::string& display_id,
+                       const api::system_display::DisplayProperties& info,
+                       std::string* error) OVERRIDE;
+  virtual void UpdateDisplayUnitInfoForPlatform(
+      const gfx::Display& display,
+      extensions::api::system_display::DisplayUnitInfo* unit) OVERRIDE;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DisplayInfoProviderMac);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_DISPLAY_INFO_PROVIDER_MAC_H_