Support input events in Chrome ASH on Windows 7.

win8/metro_driver/display_properties.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 "stdafx.h"
 
 #include <windows.h>
 #include <wrl\implements.h>
 #include <wrl\wrappers\corewrappers.h>
 #include <windows.foundation.h>
 #include <windows.graphics.display.h>
+#include "base/win/windows_version.h"
 #include "ui/gfx/win/dpi.h"
 #include "winrt_utils.h"
 
 float GetModernUIScale() {
-  Microsoft::WRL::ComPtr<
-      ABI::Windows::Graphics::Display::IDisplayPropertiesStatics>
-      display_properties;
-  if (SUCCEEDED(winrt_utils::CreateActivationFactory(
-      RuntimeClass_Windows_Graphics_Display_DisplayProperties,
-      display_properties.GetAddressOf()))) {
-    ABI::Windows::Graphics::Display::ResolutionScale resolution_scale;
-    if (SUCCEEDED(display_properties->get_ResolutionScale(&resolution_scale)))
-      return static_cast<float>(resolution_scale) / 100.0f;
+  if (base::win::GetVersion() >= base::win::VERSION_WIN8) {
+    Microsoft::WRL::ComPtr<
+        ABI::Windows::Graphics::Display::IDisplayPropertiesStatics>
+        display_properties;
+    if (SUCCEEDED(winrt_utils::CreateActivationFactory(
+        RuntimeClass_Windows_Graphics_Display_DisplayProperties,
+        display_properties.GetAddressOf()))) {
+      ABI::Windows::Graphics::Display::ResolutionScale resolution_scale;
+      if (SUCCEEDED(display_properties->get_ResolutionScale(&resolution_scale)))
+        return static_cast<float>(resolution_scale) / 100.0f;
+    }
   }
-  return 1.0f;
+  return gfx::GetDPIScale();
 }