Set the scale factor for the display on Windows when in high-DPI mode.

ui/gfx/screen_win.cc

 // Copyright (c) 2012 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 "ui/gfx/screen_win.h"
 
 #include <windows.h>
 
 #include "base/logging.h"
+#include "ui/base/win/dpi.h"
 #include "ui/gfx/display.h"
 
 namespace {
 
 MONITORINFO GetMonitorInfoForMonitor(HMONITOR monitor) {
   MONITORINFO monitor_info = { 0 };
   monitor_info.cbSize = sizeof(monitor_info);
   GetMonitorInfo(monitor, &monitor_info);
   return monitor_info;
 }
 
 gfx::Display GetDisplay(MONITORINFO& monitor_info) {
   // TODO(oshima): Implement ID and Observer.
   gfx::Display display(0, gfx::Rect(monitor_info.rcMonitor));

[oshima, 2013/03/04 22:12:02]

Oh, wait. So this was wrong? Or size of rcMonitor ==
size of rcWork?

-  display.set_work_area(gfx::Rect(monitor_info.rcWork));
+  gfx::Rect work_area = gfx::Rect(monitor_info.rcWork);
+  display.set_work_area(work_area);
+  display.SetScaleAndBounds(ui::win::GetDeviceScaleFactor(), work_area);

[oshima, 2013/03/04 19:34:25]

I believe you need to pass the display's bound (in pixel) instead of work area
here, unless the meaning of work area
is different on windows.

Another q: I thought windows desktop and modern UI can
have different scale factors. Am I wrong or are you going
to address this later?

[kevers, 2013/03/04 20:02:14]

For Windows, the scale factor is fixed across all devices and based on the
DPI-scale factor, which is set as an OS preference.  Requires relogging for a
change in scale factor to take effect.

Will investigate if the display's bounds should be used.

[girard, 2013/03/04 21:53:45]

The "work area" on windows is the area excluding OS controls (like the toolbar),
so this code is correct.
Windows does not support multiple simultaneous scale factors, so we won't have
to worry about this.

   return display;
 }
 
 }  // namespace
 
 namespace gfx {
 
 ScreenWin::ScreenWin() {
 }
 
@@ skipping 96 matching lines @@
 #endif  // USE_AURA
 }
 
 #if !defined(USE_AURA)
 Screen* CreateNativeScreen() {
   return new ScreenWin;
 }
 #endif  // !USE_AURA
 
 }  // namespace gfx