--- a/layout/style/nsMediaFeatures.cpp
+++ b/layout/style/nsMediaFeatures.cpp
@@ -255,25 +255,17 @@ GetMonochrome(nsPresContext* aPresContex
 }
 
 static nsresult
 GetResolution(nsPresContext* aPresContext, const nsMediaFeature*,
               nsCSSValue& aResult)
 {
     // Resolution measures device pixels per CSS (inch/cm/pixel).  We
     // return it in device pixels per CSS inches.
-    //
-    // However, on platforms where the CSS viewport is not fixed to the
-    // screen viewport, use the device resolution instead (bug 779527).
-    nsIPresShell *shell = aPresContext->PresShell();
-    float appUnitsPerInch = shell->GetIsViewportOverridden() ?
-            GetDeviceContextFor(aPresContext)->AppUnitsPerPhysicalInch() :
-            nsPresContext::AppUnitsPerCSSInch();
-
-    float dpi = appUnitsPerInch /
+    float dpi = float(nsPresContext::AppUnitsPerCSSInch()) /
                 float(aPresContext->AppUnitsPerDevPixel());
     aResult.SetFloatValue(dpi, eCSSUnit_Inch);
     return NS_OK;
 }
 
 static nsresult
 GetScan(nsPresContext* aPresContext, const nsMediaFeature*,
         nsCSSValue& aResult)