diff -r 000000000000 -r 6474c204b198 widget/windows/winrt/MetroUtils.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/windows/winrt/MetroUtils.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,190 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MetroUtils.h"
+#include <windows.h>
+#include "nsICommandLineRunner.h"
+#include "nsNetUtil.h"
+#include "nsIBrowserDOMWindow.h"
+#include "nsIWebNavigation.h"
+#include "nsIDocShellTreeItem.h"
+#include "nsIDOMWindow.h"
+#include "nsIDOMChromeWindow.h"
+#include "nsIWindowMediator.h"
+#include "nsIURI.h"
+#include "prlog.h"
+#include "nsIObserverService.h"
+#include "nsRect.h"
+
+#include <wrl/wrappers/corewrappers.h>
+#include <windows.ui.applicationsettings.h>
+#include <windows.graphics.display.h>
+#include "DisplayInfo_sdk81.h"
+
+using namespace ABI::Windows::UI::ApplicationSettings;
+
+using namespace mozilla;
+
+using namespace ABI::Windows::Foundation;
+using namespace Microsoft::WRL;
+using namespace Microsoft::WRL::Wrappers;
+using namespace ABI::Windows::UI::ViewManagement;
+using namespace ABI::Windows::Graphics::Display;
+
+// Conversion between logical and physical coordinates
+
+double
+MetroUtils::LogToPhysFactor()
+{
+  ComPtr<IDisplayInformationStatics> dispInfoStatics;
+  if (SUCCEEDED(GetActivationFactory(HStringReference(RuntimeClass_Windows_Graphics_Display_DisplayInformation).Get(),
+                                      dispInfoStatics.GetAddressOf()))) {
+    ComPtr<IDisplayInformation> dispInfo;
+    if (SUCCEEDED(dispInfoStatics->GetForCurrentView(&dispInfo))) {
+      FLOAT dpi;
+      if (SUCCEEDED(dispInfo->get_LogicalDpi(&dpi))) {
+        return (double)dpi / 96.0f;
+      }
+    }
+  }
+
+  ComPtr<IDisplayPropertiesStatics> dispProps;
+  if (SUCCEEDED(GetActivationFactory(HStringReference(RuntimeClass_Windows_Graphics_Display_DisplayProperties).Get(),
+                                      dispProps.GetAddressOf()))) {
+    FLOAT dpi;
+    if (SUCCEEDED(dispProps->get_LogicalDpi(&dpi))) {
+      return (double)dpi / 96.0f;
+    }
+  }
+
+  return 1.0;
+}
+
+double
+MetroUtils::PhysToLogFactor()
+{
+  return 1.0 / LogToPhysFactor();
+}
+
+double
+MetroUtils::ScaleFactor()
+{
+  // Return the resolution scale factor reported by the metro environment.
+  // XXX TODO: also consider the desktop resolution setting, as IE appears to do?
+  ComPtr<IDisplayInformationStatics> dispInfoStatics;
+  if (SUCCEEDED(GetActivationFactory(HStringReference(RuntimeClass_Windows_Graphics_Display_DisplayInformation).Get(),
+                                      dispInfoStatics.GetAddressOf()))) {
+    ComPtr<IDisplayInformation> dispInfo;
+    if (SUCCEEDED(dispInfoStatics->GetForCurrentView(&dispInfo))) {
+      ResolutionScale scale;
+      if (SUCCEEDED(dispInfo->get_ResolutionScale(&scale))) {
+        return (double)scale / 100.0;
+      }
+    }
+  }
+
+  ComPtr<IDisplayPropertiesStatics> dispProps;
+  if (SUCCEEDED(GetActivationFactory(HStringReference(RuntimeClass_Windows_Graphics_Display_DisplayProperties).Get(),
+                                     dispProps.GetAddressOf()))) {
+    ResolutionScale scale;
+    if (SUCCEEDED(dispProps->get_ResolutionScale(&scale))) {
+      return (double)scale / 100.0;
+    }
+  }
+
+  return 1.0;
+}
+
+nsIntPoint
+MetroUtils::LogToPhys(const Point& aPt)
+{
+  double factor = LogToPhysFactor();
+  return nsIntPoint(int32_t(NS_round(aPt.X * factor)), int32_t(NS_round(aPt.Y * factor)));
+}
+
+nsIntRect
+MetroUtils::LogToPhys(const Rect& aRect)
+{
+  double factor = LogToPhysFactor();
+  return nsIntRect(int32_t(NS_round(aRect.X * factor)),
+                   int32_t(NS_round(aRect.Y * factor)),
+                   int32_t(NS_round(aRect.Width * factor)),
+                   int32_t(NS_round(aRect.Height * factor)));
+}
+
+Point
+MetroUtils::PhysToLog(const nsIntPoint& aPt)
+{
+  // Points contain FLOATs
+  FLOAT factor = (FLOAT)PhysToLogFactor();
+  Point p = { FLOAT(aPt.x) * factor, FLOAT(aPt.y) * factor };
+  return p;
+}
+
+nsresult
+MetroUtils::FireObserver(const char* aMessage, const char16_t* aData)
+{
+  nsCOMPtr<nsIObserverService> observerService =
+    mozilla::services::GetObserverService();
+  if (observerService) {
+    return observerService->NotifyObservers(nullptr, aMessage, aData);
+  }
+  return NS_ERROR_FAILURE;
+}
+
+HRESULT MetroUtils::CreateUri(HSTRING aUriStr, ComPtr<IUriRuntimeClass>& aUriOut)
+{
+  HRESULT hr;
+  ComPtr<IUriRuntimeClassFactory> uriFactory;
+  hr = GetActivationFactory(HStringReference(RuntimeClass_Windows_Foundation_Uri).Get(), &uriFactory);
+  AssertRetHRESULT(hr, hr);
+  ComPtr<IUriRuntimeClass> uri;
+  return uriFactory->CreateUri(aUriStr, &aUriOut);
+}
+
+HRESULT MetroUtils::CreateUri(HString& aHString, ComPtr<IUriRuntimeClass>& aUriOut)
+{
+  return MetroUtils::CreateUri(aHString.Get(), aUriOut);
+}
+
+HRESULT
+MetroUtils::GetViewState(ApplicationViewState& aState)
+{
+  HRESULT hr;
+  ComPtr<IApplicationViewStatics> appViewStatics;
+  hr = GetActivationFactory(HStringReference(RuntimeClass_Windows_UI_ViewManagement_ApplicationView).Get(),
+    appViewStatics.GetAddressOf());
+  AssertRetHRESULT(hr, hr);
+  hr = appViewStatics->get_Value(&aState);
+  return hr;
+}
+
+HRESULT
+MetroUtils::TryUnsnap(bool* aResult)
+{
+  HRESULT hr;
+  ComPtr<IApplicationViewStatics> appViewStatics;
+  hr = GetActivationFactory(HStringReference(RuntimeClass_Windows_UI_ViewManagement_ApplicationView).Get(),
+    appViewStatics.GetAddressOf());
+  AssertRetHRESULT(hr, hr);
+  boolean success = false;
+  hr = appViewStatics->TryUnsnap(&success);
+  if (aResult)
+    *aResult = success;
+  return hr;
+}
+
+HRESULT
+MetroUtils::ShowSettingsFlyout()
+{
+  ComPtr<ISettingsPaneStatics> settingsPaneStatics;
+  HRESULT hr = GetActivationFactory(HStringReference(RuntimeClass_Windows_UI_ApplicationSettings_SettingsPane).Get(),
+                                    settingsPaneStatics.GetAddressOf());
+  if (SUCCEEDED(hr)) {
+    settingsPaneStatics->Show();
+  }
+
+  return hr;
+}