Bug 1458121 - Don't try to layerize when we have a clip-path mask as well as rounded rect clipping. r=mstange

MozReview-Commit-ID: GhOay2a6z9t

--HG--
extra : rebase_source : 2c3dcf4fe05046da1790a46fb96d7acdf7caf86c

layout/base/crashtests/1458121.html

@@ -0,0 +1,23 @@
+<script>
+window.requestIdleCallback(function(){
+  document.documentElement.style.display="none";
+  document.documentElement.getBoundingClientRect();
+  document.documentElement.style.display="";
+});
+</script>
+<style>
+body {
+  -webkit-border-radius: 16px;
+  overflow-x: hidden;
+  -webkit-filter: blur(0px);
+  width: 1em;
+}
+:root {
+  scroll-snap-destination: left top 36%;
+}
+#a {
+  overflow: scroll;
+  clip-path: url(#x);
+}
+</style>
+<dl id="a">|<dialog open>

layout/base/crashtests/crashtests.list

@@ -538,6 +538,7 @@ load 1452839.html
 load 1453196.html
 load 1453342.html
 load 1453702.html
+load 1458121.html
 pref(dom.webcomponents.shadowdom.enabled,true) load 1461749.html
 load 1461812.html
 load 1462412.html

layout/painting/nsDisplayList.cpp

@@ -9250,6 +9250,12 @@ bool nsDisplayMask::CanPaintOnMaskLayer(LayerManager* aManager)
     return false;
   }
 
+  // We don't currently support this item creating a mask
+  // for both the clip-path, and rounded rect clipping.
+  if (GetClip().GetRoundedRectCount() != 0) {
+    return false;
+  }
+
   return true;
 }