Make DisplayInfoProvider an interface

chrome/browser/extensions/api/system_display/display_info_provider_win.cc

-// Copyright 2013 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 "chrome/browser/extensions/api/system_display/display_info_provider.h"
-
-#include <windows.h>
-
-#include "base/hash.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/win/win_util.h"
-#include "ui/gfx/size.h"
-#include "ui/gfx/win/dpi.h"
-
-namespace extensions {
-
-using api::system_display::DisplayUnitInfo;
-
-namespace {
-
-BOOL CALLBACK EnumMonitorCallback(HMONITOR monitor,
-                                  HDC hdc,
-                                  LPRECT rect,
-                                  LPARAM data) {
-  DisplayInfo* all_displays = reinterpret_cast<DisplayInfo*>(data);
-  DCHECK(all_displays);
-
-  linked_ptr<DisplayUnitInfo> unit(new DisplayUnitInfo);
-
-  MONITORINFOEX monitor_info;
-  ZeroMemory(&monitor_info, sizeof(MONITORINFOEX));
-  monitor_info.cbSize = sizeof(monitor_info);
-  GetMonitorInfo(monitor, &monitor_info);
-
-  DISPLAY_DEVICE device;
-  device.cb = sizeof(device);
-  if (!EnumDisplayDevices(monitor_info.szDevice, 0, &device, 0))
-    return FALSE;
-
-  gfx::Size dpi(gfx::GetDPI());
-  unit->id = base::Int64ToString(
-      base::Hash(base::WideToUTF8(monitor_info.szDevice)));
-  unit->name = base::WideToUTF8(device.DeviceString);
-  unit->dpi_x = dpi.width();
-  unit->dpi_y = dpi.height();
-  all_displays->push_back(unit);
-
-  return TRUE;
-}
-
-}  // namespace
-
-bool DisplayInfoProvider::SetInfo(const std::string& display_id,
-    const api::system_display::DisplayProperties& info,
-    std::string* error) {
-  *error = "Not implemented";
-  return false;
-}
-
-void DisplayInfoProvider::UpdateDisplayUnitInfoForPlatform(
-    const gfx::Display& display,
-    extensions::api::system_display::DisplayUnitInfo* unit) {
-  DisplayInfo all_displays;
-  EnumDisplayMonitors(NULL, NULL, EnumMonitorCallback,
-                      reinterpret_cast<LPARAM>(&all_displays));
-  for (size_t i = 0; i < all_displays.size(); ++i) {
-    if (unit->id == all_displays[i]->id) {
-      unit->name = all_displays[i]->name;
-      unit->dpi_x = all_displays[i]->dpi_x;
-      unit->dpi_y = all_displays[i]->dpi_y;
-      break;
-    }
-  }
-}
-
-}  // namespace extensions