diff --git a/layout/base/FrameLayerBuilder.cpp b/layout/base/FrameLayerBuilder.cpp
index 60b69a9578d..7432e1f7602 100644
--- a/layout/base/FrameLayerBuilder.cpp
+++ b/layout/base/FrameLayerBuilder.cpp
@@ -491,7 +491,7 @@ public:
     return aRegion.ScaleToNearestPixels(mParameters.mXScale, mParameters.mYScale,
                                         mAppUnitsPerDevPixel);
   }
-  nsIntRect ScaleToOutsidePixels(const nsRect& aRect, bool aSnap)
+  nsIntRect ScaleToOutsidePixels(const nsRect& aRect, bool aSnap = false)
   {
     if (aSnap && mSnappingEnabled) {
       return ScaleToNearestPixels(aRect);
@@ -499,7 +499,7 @@ public:
     return aRect.ScaleToOutsidePixels(mParameters.mXScale, mParameters.mYScale,
                                       mAppUnitsPerDevPixel);
   }
-  nsIntRect ScaleToInsidePixels(const nsRect& aRect, bool aSnap)
+  nsIntRect ScaleToInsidePixels(const nsRect& aRect, bool aSnap = false)
   {
     if (aSnap && mSnappingEnabled) {
       return ScaleToNearestPixels(aRect);
@@ -508,7 +508,7 @@ public:
                                      mAppUnitsPerDevPixel);
   }
 
-  nsIntRegion ScaleRegionToInsidePixels(const nsRegion& aRegion, bool aSnap)
+  nsIntRegion ScaleRegionToInsidePixels(const nsRegion& aRegion, bool aSnap = false)
   {
     if (aSnap && mSnappingEnabled) {
       return ScaleRegionToNearestPixels(aRegion);
@@ -517,6 +517,15 @@ public:
                                         mAppUnitsPerDevPixel);
   }
 
+  nsIntRegion ScaleRegionToOutsidePixels(const nsRegion& aRegion, bool aSnap = false)
+  {
+    if (aSnap && mSnappingEnabled) {
+      return ScaleRegionToNearestPixels(aRegion);
+    }
+    return aRegion.ScaleToOutsidePixels(mParameters.mXScale, mParameters.mYScale,
+                                        mAppUnitsPerDevPixel);
+  }
+
 protected:
   friend class ThebesLayerData;