Bug 1458145 - Extend the ASR adjustment performed on perspective items, to a wrapping OwnLayer item as well. r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D100144

layout/painting/FrameLayerBuilder.cpp

@@ -4891,15 +4891,21 @@ void ContainerState::ProcessDisplayItems(nsDisplayList* aList) {
         params.mCompositorASR = itemASR;
       }
 
-      if (itemType == DisplayItemType::TYPE_PERSPECTIVE) {
       // Perspective items have a single child item, an nsDisplayTransform.
       // If the perspective item is scrolled, but the perspective-inducing
       // frame is outside the scroll frame (indicated by item->Frame()
       // being outside that scroll frame), we have to take special care to
       // make APZ scrolling work properly. APZ needs us to put the scroll
       // frame's FrameMetrics on our child transform ContainerLayer instead.
+      // We make a similar adjustment for OwnLayer items built for frames
+      // with perspective transforms (e.g. when they have rounded corners).
       // It's worth investigating whether this ASR adjustment can be done at
       // display item creation time.
+      bool deferASRForPerspective =
+          itemType == DisplayItemType::TYPE_PERSPECTIVE ||
+          (itemType == DisplayItemType::TYPE_OWN_LAYER &&
+           item->Frame()->IsTransformed() && item->Frame()->HasPerspective());
+      if (deferASRForPerspective) {
         scrollMetadataASR = GetASRForPerspective(
             scrollMetadataASR,
             item->Frame()->GetContainingBlock(nsIFrame::SKIP_SCROLLED_FRAME));

layout/painting/crashtests/1458145.html

@@ -0,0 +1,11 @@
+<style>
+* { position: fixed; }
+#a {
+perspective: 0px;
+overflow: scroll;
+}
+.cl2 { -webkit-transform-style: preserve-3d; }
+.cl1 { border-bottom-right-radius: 0px 1px; }
+</style>
+<del id="a" class="cl1">
+<dl class="cl2">#_k</dl>

layout/painting/crashtests/crashtests.list

@@ -11,6 +11,7 @@ load 1428906-1.html
 load 1430589-1.html
 load 1454105-1.html
 load 1455944-1.html
+load 1458145.html
 load 1465305-1.html
 load 1468124-1.html
 load 1469472.html