--- a/layout/reftests/w3c-css/submitted/masking/reftest.list
+++ b/layout/reftests/w3c-css/submitted/masking/reftest.list
@@ -1,10 +1,94 @@
 # For those test items with failure type fuzzy-if added, please refer to bug 1231643#c10.
 
+== mask-image-5.html mask-image-5-ref.html
+== mask-image-1d.html mask-image-1-ref.html
+== mask-image-6.html mask-image-6-ref.html
+
+default-preferences pref(layout.css.positioned-mask.enabled,false)
+
+# mask-composite test cases
+fails == mask-composite-1a.html mask-composite-1-ref.html
+fails == mask-composite-1b.html mask-composite-1-ref.html
+fails == mask-composite-1c.html mask-composite-1-ref.html
+fails == mask-composite-2a.html mask-composite-2-ref.html
+fails == mask-composite-2b.html mask-composite-2-ref.html
+fails == mask-composite-2c.html mask-composite-2-ref.html
+
+# mask-mode test cases
+fails == mask-mode-a.html mask-mode-ref.html
+fails == mask-mode-b.html mask-mode-ref.html
+fails == mask-mode-to-mask-type.html mask-mode-to-mask-type-ref.html
+
+# mask-image test cases
+fails == mask-image-1a.html mask-image-1-ref.html
+fails == mask-image-1b.html mask-image-1-ref.html
+fails == mask-image-1c.html mask-image-1-ref.html
+fails == mask-image-2.html mask-image-2-ref.html
+fails == mask-image-3a.html mask-image-3-ref.html
+fails == mask-image-3b.html mask-image-3-ref.html
+fails == mask-image-3c.html mask-image-3-ref.html
+fails == mask-image-3d.html mask-image-3-ref.html
+fails == mask-image-3e.html mask-image-3-ref.html
+fails == mask-image-3f.html mask-image-3-ref.html
+fails == mask-image-3g.html mask-image-3-ref.html
+fails == mask-image-4a.html blank.html
+fails == mask-image-4b.html blank.html
+
+# mask-clip test cases
+fails == mask-clip-1.html mask-clip-1-ref.html
+
+# mask-position test cases
+fails == mask-position-1a.html mask-position-1-ref.html
+fails == mask-position-1b.html mask-position-1-ref.html
+fails == mask-position-1c.html mask-position-1-ref.html
+fails == mask-position-2a.html mask-position-2-ref.html
+fails == mask-position-2b.html mask-position-2-ref.html
+fails == mask-position-3a.html mask-position-3-ref.html
+fails == mask-position-3b.html mask-position-3-ref.html
+fails == mask-position-4a.html mask-position-4-ref.html
+fails == mask-position-4b.html mask-position-4-ref.html
+fails == mask-position-4c.html mask-position-4-ref.html
+fails == mask-position-4d.html mask-position-4-ref.html
+fails == mask-position-5.html mask-position-5-ref.html
+fails == mask-position-6.html mask-position-6-ref.html
+fails == mask-position-7.html mask-position-7-ref.html
+
+# mask-repeat test cases
+fails == mask-repeat-1.html mask-repeat-1-ref.html
+fails == mask-repeat-2.html mask-repeat-2-ref.html
+fails == mask-repeat-3.html mask-repeat-3-ref.html
+
+# mask-origin test cases
+fails == mask-origin-1.html mask-origin-1-ref.html
+fails == mask-origin-2.html mask-origin-2-ref.html # bug 1260094
+
+# mask-size test cases
+fails == mask-size-auto.html mask-size-auto-ref.html
+fails == mask-size-auto-auto.html mask-size-auto-ref.html
+fails == mask-size-auto-length.html mask-size-auto-length-ref.html
+fails == mask-size-auto-percent.html mask-size-auto-length-ref.html
+fails == mask-size-contain-clip-border.html mask-size-contain-clip-border-ref.html
+fails == mask-size-contain-clip-padding.html mask-size-contain-clip-padding-ref.html
+fails == mask-size-contain-position-fifty-fifty.html mask-size-contain-position-fifty-fifty-ref.html
+fails == mask-size-contain.html mask-size-contain-ref.html
+fails == mask-size-cover.html mask-size-cover-ref.html
+fails == mask-size-length.html mask-size-length-length-ref.html
+fails == mask-size-length-auto.html mask-size-length-length-ref.html
+fails == mask-size-length-length.html mask-size-length-length-ref.html
+fails == mask-size-length-percent.html mask-size-length-percent-ref.html
+fails == mask-size-percent.html mask-size-percent-percent-ref.html
+fails == mask-size-percent-auto.html mask-size-percent-percent-ref.html
+fails == mask-size-percent-length.html mask-size-percent-percent-ref.html
+fails == mask-size-percent-percent.html mask-size-percent-percent-ref.html
+fails == mask-size-percent-percent-stretch.html mask-size-percent-percent-stretch-ref.html
+
+default-preferences pref(layout.css.positioned-mask.enabled,true)
+
 # mask-composite test cases
 == mask-composite-1a.html mask-composite-1-ref.html
 fuzzy-if(skiaContent,64,200) == mask-composite-1b.html mask-composite-1-ref.html
 == mask-composite-1c.html mask-composite-1-ref.html
 fuzzy-if(skiaContent||winWidget,1,5000) == mask-composite-2a.html mask-composite-2-ref.html
 fuzzy-if(skiaContent||winWidget,64,5200) == mask-composite-2b.html mask-composite-2-ref.html
 == mask-composite-2c.html mask-composite-2-ref.html
 
@@ -12,29 +96,26 @@ fuzzy-if(skiaContent||winWidget,64,5200)
 fuzzy-if(skiaContent,1,30000) == mask-mode-a.html mask-mode-ref.html
 fuzzy-if(skiaContent,1,30000) == mask-mode-b.html mask-mode-ref.html
 fuzzy-if(skiaContent,1,30000) == mask-mode-to-mask-type.html mask-mode-to-mask-type-ref.html
 
 # mask-image test cases
 == mask-image-1a.html mask-image-1-ref.html
 == mask-image-1b.html mask-image-1-ref.html
 == mask-image-1c.html mask-image-1-ref.html
-== mask-image-1d.html mask-image-1-ref.html
 fuzzy-if(skiaContent||winWidget,1,20000) == mask-image-2.html mask-image-2-ref.html
 == mask-image-3a.html mask-image-3-ref.html
 == mask-image-3b.html mask-image-3-ref.html
 fuzzy-if(skiaContent||winWidget,1,43) == mask-image-3c.html mask-image-3-ref.html
 fuzzy-if(skiaContent||winWidget,1,43) == mask-image-3d.html mask-image-3-ref.html
 == mask-image-3e.html mask-image-3-ref.html
 fuzzy-if(skiaContent,50,50) == mask-image-3f.html mask-image-3-ref.html
 == mask-image-3g.html mask-image-3-ref.html
 == mask-image-4a.html blank.html
 == mask-image-4b.html blank.html
-== mask-image-5.html mask-image-5-ref.html
-== mask-image-6.html mask-image-6-ref.html
 
 # mask-clip test cases
 == mask-clip-1.html mask-clip-1-ref.html
 
 # mask-position test cases
 == mask-position-1a.html mask-position-1-ref.html
 == mask-position-1b.html mask-position-1-ref.html
 == mask-position-1c.html mask-position-1-ref.html
@@ -103,9 +184,9 @@ fuzzy-if(winWidget,9,98) == clip-path-ge
 
 default-preferences
 
 # mask with opacity test cases
 fuzzy(1,5000) == mask-opacity-1a.html mask-opacity-1-ref.html
 fuzzy(1,5000) == mask-opacity-1b.html mask-opacity-1-ref.html
 fuzzy(1,5000) == mask-opacity-1c.html mask-opacity-1-ref.html
 
-== clip-path-mix-blend-mode-1.html clip-path-mix-blend-mode-1-ref.html
\ No newline at end of file
+== clip-path-mix-blend-mode-1.html clip-path-mix-blend-mode-1-ref.html