Multiple DPI Tracking for ScreenWin

chrome/browser/extensions/display_info_provider_win.cc

 // 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 "chrome/browser/extensions/display_info_provider_win.h"
 
 #include <windows.h>
 #include <stddef.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 "extensions/common/api/system_display.h"
+#include "ui/gfx/display.h"
 #include "ui/gfx/geometry/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
 
 DisplayInfoProviderWin::DisplayInfoProviderWin() {
 }
 
@@ skipping 10 matching lines @@
 
 void DisplayInfoProviderWin::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;
+      int dpi = gfx::GetDPIFromScalingFactor(display.device_scale_factor());
+      unit->dpi_x = dpi;
+      unit->dpi_y = dpi;
       break;
     }
   }
 }
 
 // static
 DisplayInfoProvider* DisplayInfoProvider::Create() {
   return new DisplayInfoProviderWin();
 }
 
 }  // namespace extensions