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

win8/metro_driver/direct3d_helper.cc

Index: win8/metro_driver/direct3d_helper.cc
diff --git a/win8/metro_driver/direct3d_helper.cc b/win8/metro_driver/direct3d_helper.cc
index d0c30cf71219f1d024854e1c25f7f3b4b22291ab..0e62a640e627416d3f5265b47436a232a16b7441 100644
--- a/win8/metro_driver/direct3d_helper.cc
+++ b/win8/metro_driver/direct3d_helper.cc
@@ -13,6 +13,8 @@
 #include <windows.applicationmodel.core.h>
 #include <windows.graphics.display.h>
 
+#include "ui/gfx/win/dpi.h"
+
 namespace {
 
 void CheckIfFailed(HRESULT hr) {
@@ -21,6 +23,10 @@ void CheckIfFailed(HRESULT 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(
@@ -32,9 +38,7 @@ float GetLogicalDpi() {
 }
 
 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);
 }
 
 }