Use the win32 device scale factor in Chrome ASH on Windows.

win8/metro_driver/direct3d_helper.cc

 // Copyright 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 "stdafx.h"
 #include "win8/metro_driver/direct3d_helper.h"
 #include "win8/metro_driver/winrt_utils.h"
 
 #include "base/logging.h"
 #include "base/win/windows_version.h"
 
 #include <corewindow.h>
 #include <windows.applicationmodel.core.h>
 #include <windows.graphics.display.h>
 
+#include "ui/gfx/win/dpi.h"
+
 namespace {
 
 void CheckIfFailed(HRESULT hr) {
   DCHECK(!FAILED(hr));
   if (FAILED(hr))
     DVLOG(0) << "Direct3D call failed, hr = " << hr;
 }
 
+// TODO(ananta)
+// This function does not return the correct value as the IDisplayProperties
+// interface does not work correctly in Windows 8 in metro mode. Needs
+// more investigation.
 float GetLogicalDpi() {
   mswr::ComPtr<wingfx::Display::IDisplayPropertiesStatics> display_properties;
   CheckIfFailed(winrt_utils::CreateActivationFactory(
       RuntimeClass_Windows_Graphics_Display_DisplayProperties,
       display_properties.GetAddressOf()));
   float dpi = 0.0;
   CheckIfFailed(display_properties->get_LogicalDpi(&dpi));
   return dpi;
 }
 
 float ConvertDipsToPixels(float dips) {
-  static const float dips_per_inch = 96.f;
-  float logical_dpi = GetLogicalDpi();
-  return floor(dips * logical_dpi / dips_per_inch + 0.5f);
+  return floor(dips * gfx::GetDPIScale() + 0.5f);
 }
 
 }
 
 namespace metro_driver {
 
 Direct3DHelper::Direct3DHelper() {
 }
 
 Direct3DHelper::~Direct3DHelper() {
@@ skipping 100 matching lines @@
           window,
           &swap_chain_desc,
           nullptr,
           nullptr,
           &swap_chain_));
     }
   }
 }
 
 }  // namespace metro_driver