Bug 1388626. Restyle ::-moz-xul-anonymous-block as needed with stylo. r=heycam

MozReview-Commit-ID: KZ0s1x60VBx

--HG--
extra : rebase_source : d7103464e7563ae7105417f254609cb22481e0e3

layout/base/nsCSSFrameConstructor.cpp

@@ -11385,6 +11385,9 @@ nsCSSFrameConstructor::ProcessChildren(nsFrameConstructorState& aState,
     aFrameItems.AddChild(blockFrame);
 
     aFrame->AddStateBits(NS_STATE_BOX_WRAPS_KIDS_IN_BLOCK);
+    MOZ_ASSERT(!aFrame->IsLeaf(),
+               "Why do we have an nsLeafBoxFrame here?");
+    aFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);
   }
 }
 

layout/xul/nsBoxFrame.cpp

@@ -1908,6 +1908,14 @@ nsBoxFrame::SupportsOrdinalsInChildren()
   return true;
 }
 
+void
+nsBoxFrame::AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult)
+{
+  if (GetStateBits() & NS_STATE_BOX_WRAPS_KIDS_IN_BLOCK) {
+    aResult.AppendElement(OwnedAnonBox(PrincipalChildList().FirstChild()));
+  }
+}
+
 // Helper less-than-or-equal function, used in CheckBoxOrder() as a
 // template-parameter for the sorting functions.
 bool

layout/xul/nsBoxFrame.h

@@ -171,6 +171,11 @@ public:
    */
   virtual bool SupportsOrdinalsInChildren();
 
+  /**
+   * Return our wrapper block, if any.
+   */
+  void AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult) override;
+
 private:
   explicit nsBoxFrame(nsStyleContext* aContext)
     : nsBoxFrame(aContext, kClassID, false, nullptr) {}