--- a/browser/modules/Windows8WindowFrameColor.jsm
+++ b/browser/modules/Windows8WindowFrameColor.jsm
@@ -26,17 +26,17 @@ const Windows8WindowFrameColor = {
       // Seems to be the default color (hardcoded because of bug 1065998)
       return [158, 158, 158];
     }
     // The color returned from the Registry is in decimal form.
     let customizationColorHex = customizationColor.toString(16);
     // Zero-pad the number just to make sure that it is 8 digits.
     customizationColorHex = ("00000000" + customizationColorHex).substr(-8);
     let customizationColorArray = customizationColorHex.match(/../g);
-    let [unused, fgR, fgG, fgB] = customizationColorArray.map(function(val) parseInt(val, 16));
+    let [unused, fgR, fgG, fgB] = customizationColorArray.map(val => parseInt(val, 16));
     let colorizationColorBalance = Registry.readRegKey(HKCU, dwmKey,
                                                        "ColorizationColorBalance") || 78;
      // Window frame base color when Color Intensity is at 0, see bug 1004576.
     let frameBaseColor = 217;
     let alpha = colorizationColorBalance / 100;
 
     // Alpha-blend the foreground color with the frame base color.
     let r = Math.round(fgR * alpha + frameBaseColor * (1 - alpha));