Bug 1384616 - Save APZ-relevant scrollbar data into the WR scroll data for layers-free transactions. r=jrmuizel

MozReview-Commit-ID: 6DQz9N6Wq0H

--HG--
extra : rebase_source : 8a113d4a53e1562b55cc05a0bc411675a2ca9eb1

gfx/layers/wr/WebRenderScrollData.h

@@ -70,10 +70,16 @@ public:
   void SetReferentId(uint64_t aReferentId) { mReferentId = Some(aReferentId); }
   Maybe<uint64_t> GetReferentId() const { return mReferentId; }
   EventRegionsOverride GetEventRegionsOverride() const { return mEventRegionsOverride; }
+
+  void SetScrollThumbData(const ScrollThumbData& aData) { mScrollThumbData = aData; }
   const ScrollThumbData& GetScrollThumbData() const { return mScrollThumbData; }
+  void SetScrollbarAnimationId(const uint64_t& aId) { mScrollbarAnimationId = aId; }
   const uint64_t& GetScrollbarAnimationId() const { return mScrollbarAnimationId; }
+  void SetScrollbarTargetContainerId(FrameMetrics::ViewID aId) { mScrollbarTargetContainerId = aId; }
   FrameMetrics::ViewID GetScrollbarTargetContainerId() const { return mScrollbarTargetContainerId; }
+  void SetIsScrollbarContainer() { mIsScrollbarContainer = true; }
   bool IsScrollbarContainer() const { return mIsScrollbarContainer; }
+
   void SetFixedPositionScrollContainerId(FrameMetrics::ViewID aId) { mFixedPosScrollContainerId = aId; }
   FrameMetrics::ViewID GetFixedPositionScrollContainerId() const { return mFixedPosScrollContainerId; }
 

layout/painting/nsDisplayList.cpp

@@ -6390,6 +6390,28 @@ nsDisplayOwnLayer::BuildLayer(nsDisplayListBuilder* aBuilder,
   return layer.forget();
 }
 
+bool
+nsDisplayOwnLayer::UpdateScrollData(mozilla::layers::WebRenderScrollData* aData,
+                                    mozilla::layers::WebRenderLayerScrollData* aLayerData)
+{
+  bool ret = false;
+  if (IsScrollThumbLayer()) {
+    ret = true;
+    if (aLayerData) {
+      aLayerData->SetScrollThumbData(mThumbData);
+      aLayerData->SetScrollbarTargetContainerId(mScrollTarget);
+    }
+  }
+  if (mFlags & SCROLLBAR_CONTAINER) {
+    ret = true;
+    if (aLayerData) {
+      aLayerData->SetIsScrollbarContainer();
+      aLayerData->SetScrollbarTargetContainerId(mScrollTarget);
+    }
+  }
+  return ret;
+}
+
 nsDisplaySubDocument::nsDisplaySubDocument(nsDisplayListBuilder* aBuilder,
                                            nsIFrame* aFrame, nsDisplayList* aList,
                                            uint32_t aFlags)
@@ -6697,7 +6719,7 @@ nsDisplayFixedPosition::UpdateScrollData(mozilla::layers::WebRenderScrollData* a
         Frame()->PresContext());
     aLayerData->SetFixedPositionScrollContainerId(id);
   }
-  return true;
+  return nsDisplayOwnLayer::UpdateScrollData(aData, aLayerData) | true;
 }
 
 TableType

layout/painting/nsDisplayList.h

@@ -4150,6 +4150,8 @@ public:
   virtual already_AddRefed<Layer> BuildLayer(nsDisplayListBuilder* aBuilder,
                                              LayerManager* aManager,
                                              const ContainerLayerParameters& aContainerParameters) override;
+  virtual bool UpdateScrollData(mozilla::layers::WebRenderScrollData* aData,
+                                mozilla::layers::WebRenderLayerScrollData* aLayerData) override;
   virtual LayerState GetLayerState(nsDisplayListBuilder* aBuilder,
                                    LayerManager* aManager,
                                    const ContainerLayerParameters& aParameters) override;