Bug 1064843 part 6 - Add backdrop frame list. r=dholbert

layout/generic/FrameChildList.cpp

@@ -46,6 +46,7 @@ ChildListName(FrameChildListID aListID)
     case kFloatList: return "FloatList";
     case kBulletList: return "BulletList";
     case kPushedFloatsList: return "PushedFloatsList";
+    case kBackdropList: return "BackdropList";
     case kNoReflowPrincipalList: return "NoReflowPrincipalList";
   }
 

layout/generic/nsContainerFrame.cpp

@@ -70,6 +70,16 @@ nsContainerFrame::SetInitialChildList(ChildListID  aListID,
     MOZ_ASSERT(mFrames.IsEmpty(),
                "unexpected second call to SetInitialChildList");
     mFrames.SetFrames(aChildList);
+  } else if (aListID == kBackdropList) {
+    MOZ_ASSERT(StyleDisplay()->mTopLayer != NS_STYLE_TOP_LAYER_NONE,
+               "Only top layer frames should have backdrop");
+    MOZ_ASSERT(GetStateBits() & NS_FRAME_OUT_OF_FLOW,
+               "Top layer frames should be out-of-flow");
+    MOZ_ASSERT(!Properties().Get(BackdropProperty()),
+               "We shouldn't have setup backdrop frame list before");
+    nsFrameList* list =
+      new (PresContext()->PresShell()) nsFrameList(aChildList);
+    Properties().Set(BackdropProperty(), list);
   } else {
     MOZ_ASSERT_UNREACHABLE("Unexpected child list");
   }
@@ -207,12 +217,16 @@ nsContainerFrame::DestroyFrom(nsIFrame* aDestructRoot)
              !(props->Get(this, nsContainerFrame::OverflowContainersProperty()) ||
                props->Get(this, nsContainerFrame::ExcessOverflowContainersProperty())),
              "this type of frame should't have overflow containers");
-
   SafelyDestroyFrameListProp(aDestructRoot, shell, props,
                              OverflowContainersProperty());
   SafelyDestroyFrameListProp(aDestructRoot, shell, props,
                              ExcessOverflowContainersProperty());
 
+  MOZ_ASSERT(!props->Get(this, BackdropProperty()) ||
+             StyleDisplay()->mTopLayer != NS_STYLE_TOP_LAYER_NONE,
+             "only top layer frame may have backdrop");
+  SafelyDestroyFrameListProp(aDestructRoot, shell, props, BackdropProperty());
+
   nsSplittableFrame::DestroyFrom(aDestructRoot);
 }
 
@@ -222,7 +236,8 @@ nsContainerFrame::DestroyFrom(nsIFrame* aDestructRoot)
 const nsFrameList&
 nsContainerFrame::GetChildList(ChildListID aListID) const
 {
-  // We only know about the principal child list and the overflow lists.
+  // We only know about the principal child list, the overflow lists,
+  // and the backdrop list.
   switch (aListID) {
     case kPrincipalList:
       return mFrames;
@@ -239,6 +254,10 @@ nsContainerFrame::GetChildList(ChildListID aListID) const
         GetPropTableFrames(ExcessOverflowContainersProperty());
       return list ? *list : nsFrameList::EmptyList();
     }
+    case kBackdropList: {
+      nsFrameList* list = GetPropTableFrames(BackdropProperty());
+      return list ? *list : nsFrameList::EmptyList();
+    }
     default:
       return nsSplittableFrame::GetChildList(aListID);
   }
@@ -270,6 +289,13 @@ nsContainerFrame::GetChildLists(nsTArray<ChildList>* aLists) const
     ::AppendIfNonempty(this, propTable, ExcessOverflowContainersProperty(),
                        aLists, kExcessOverflowContainersList);
   }
+  // Bypass BackdropProperty hashtable lookup for any in-flow frames
+  // since frames in the top layer (only which can have backdrop) are
+  // definitely out-of-flow.
+  if (GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
+    ::AppendIfNonempty(this, propTable, BackdropProperty(),
+                       aLists, kBackdropList);
+  }
   nsSplittableFrame::GetChildLists(aLists);
 }
 

layout/generic/nsContainerFrame.h

@@ -454,6 +454,7 @@ public:
   NS_DECLARE_FRAME_PROPERTY_FRAMELIST(OverflowProperty)
   NS_DECLARE_FRAME_PROPERTY_FRAMELIST(OverflowContainersProperty)
   NS_DECLARE_FRAME_PROPERTY_FRAMELIST(ExcessOverflowContainersProperty)
+  NS_DECLARE_FRAME_PROPERTY_FRAMELIST(BackdropProperty)
 
 #ifdef DEBUG
   // Use this to suppress the CRAZY_SIZE assertions.

layout/generic/nsFrameList.h

@@ -41,9 +41,10 @@ namespace layout {
       kFloatList                    = 0x800,
       kBulletList                   = 0x1000,
       kPushedFloatsList             = 0x2000,
+      kBackdropList                 = 0x4000,
       // A special alias for kPrincipalList that suppress the reflow request that
       // is normally done when manipulating child lists.
-      kNoReflowPrincipalList        = 0x4000
+      kNoReflowPrincipalList        = 0x8000
   };
 } // namespace layout
 } // namespace mozilla

layout/generic/nsIFrame.h

@@ -1086,6 +1086,7 @@ public:
   static const ChildListID kPopupList = mozilla::layout::kPopupList;
   static const ChildListID kPushedFloatsList = mozilla::layout::kPushedFloatsList;
   static const ChildListID kSelectPopupList = mozilla::layout::kSelectPopupList;
+  static const ChildListID kBackdropList = mozilla::layout::kBackdropList;
   // A special alias for kPrincipalList that do not request reflow.
   static const ChildListID kNoReflowPrincipalList = mozilla::layout::kNoReflowPrincipalList;