Backed out 3 changesets (bug 1664804) for high frequent failures at APZCTreeManager.cpp. CLOSED TREE

Backed out changeset 3d03dbc5ab3f (bug 1664804)
Backed out changeset cdc14c572652 (bug 1664804)
Backed out changeset aba3cff2d5dd (bug 1664804)

gfx/layers/ShareableCanvasRenderer.cpp

@@ -126,9 +126,6 @@ void ShareableCanvasRenderer::UpdateCompositableClient() {
   if (!YIsDown()) {
     flags |= TextureFlags::ORIGIN_BOTTOM_LEFT;
   }
-  if (IsOpaque()) {
-    flags |= TextureFlags::IS_OPAQUE;
-  }
 
   // -
 

gfx/layers/opengl/MacIOSurfaceTextureHostOGL.cpp

@@ -229,13 +229,11 @@ void MacIOSurfaceTextureHostOGL::PushDisplayItems(
     case gfx::SurfaceFormat::B8G8R8X8: {
       MOZ_ASSERT(aImageKeys.length() == 1);
       MOZ_ASSERT(mSurface->GetPlaneCount() == 0);
-      // We disable external compositing for RGB surfaces for now until
-      // we've tested support more thoroughly. Bug 1667917.
       aBuilder.PushImage(aBounds, aClip, true, aFilter, aImageKeys[0],
                          !(mFlags & TextureFlags::NON_PREMULTIPLIED),
                          wr::ColorF{1.0f, 1.0f, 1.0f, 1.0f},
                          preferCompositorSurface,
-                         /* aSupportsExternalCompositing */ false);
+                         /* aSupportsExternalCompositing */ true);
       break;
     }
     case gfx::SurfaceFormat::YUV422: {

layout/generic/ViewportFrame.cpp

@@ -113,46 +113,8 @@ static void BuildDisplayListForTopLayerFrame(nsDisplayListBuilder* aBuilder,
   aList->AppendToTop(&list);
 }
 
-static bool BackdropListIsOpaque(ViewportFrame* aFrame,
-                                 nsDisplayListBuilder* aBuilder,
-                                 nsDisplayList* aList) {
-  // The common case for ::backdrop elements on the top layer is a single
-  // fixed position container, holding an opaque background color covering
-  // the whole viewport.
-  if (aList->Count() != 1 ||
-      aList->GetTop()->GetType() != DisplayItemType::TYPE_FIXED_POSITION) {
-    return false;
-  }
-
-  // Make sure the fixed position container isn't clipped or scrollable.
-  nsDisplayFixedPosition* fixed =
-      static_cast<nsDisplayFixedPosition*>(aList->GetTop());
-  if (fixed->GetActiveScrolledRoot() || fixed->GetClipChain()) {
-    return false;
-  }
-
-  nsDisplayList* children = fixed->GetChildren();
-  if (!children->GetTop() ||
-      children->GetTop()->GetType() != DisplayItemType::TYPE_BACKGROUND_COLOR) {
-    return false;
-  }
-
-  nsDisplayBackgroundColor* child =
-      static_cast<nsDisplayBackgroundColor*>(children->GetTop());
-  if (child->GetActiveScrolledRoot() || child->GetClipChain()) {
-    return false;
-  }
-
-  // Check that the background color is both opaque, and covering the
-  // whole viewport.
-  bool dummy;
-  nsRegion opaque = child->GetOpaqueRegion(aBuilder, &dummy);
-  return opaque.Contains(aFrame->GetRect());
-}
-
 void ViewportFrame::BuildDisplayListForTopLayer(nsDisplayListBuilder* aBuilder,
-                                                nsDisplayList* aList,
-                                                bool* aIsOpaque) {
+                                                nsDisplayList* aList) {
   nsTArray<dom::Element*> topLayer = PresContext()->Document()->GetTopLayer();
   for (dom::Element* elem : topLayer) {
     if (nsIFrame* frame = elem->GetPrimaryFrame()) {
@@ -190,10 +152,6 @@ void ViewportFrame::BuildDisplayListForTopLayer(nsDisplayListBuilder* aBuilder,
             static_cast<nsPlaceholderFrame*>(backdropPh)->GetOutOfFlowFrame();
         MOZ_ASSERT(backdropFrame);
         BuildDisplayListForTopLayerFrame(aBuilder, backdropFrame, aList);
-
-        if (aIsOpaque) {
-          *aIsOpaque = BackdropListIsOpaque(this, aBuilder, aList);
-        }
       }
       BuildDisplayListForTopLayerFrame(aBuilder, frame, aList);
     }

layout/generic/ViewportFrame.h

@@ -52,8 +52,7 @@ class ViewportFrame : public nsContainerFrame {
                                 const nsDisplayListSet& aLists) override;
 
   void BuildDisplayListForTopLayer(nsDisplayListBuilder* aBuilder,
-                                   nsDisplayList* aList,
-                                   bool* aIsOpaque = nullptr);
+                                   nsDisplayList* aList);
 
   virtual nscoord GetMinISize(gfxContext* aRenderingContext) override;
   virtual nscoord GetPrefISize(gfxContext* aRenderingContext) override;

layout/generic/nsGfxScrollFrame.cpp

@@ -3637,36 +3637,28 @@ void ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder* aBuilder,
     bool addScrollBars =
         mIsRoot && mWillBuildScrollableLayer && aBuilder->IsPaintingToWindow();
 
-    nsDisplayListCollection set(aBuilder);
-
     if (addScrollBars) {
       // Add classic scrollbars.
-      AppendScrollPartsTo(aBuilder, set, createLayersForScrollbars, false);
+      AppendScrollPartsTo(aBuilder, aLists, createLayersForScrollbars, false);
     }
 
-    nsDisplayListBuilder::AutoBuildingDisplayList building(
-        aBuilder, mOuter, visibleRect, dirtyRect);
+    {
+      nsDisplayListBuilder::AutoBuildingDisplayList building(
+          aBuilder, mOuter, visibleRect, dirtyRect);
 
-    // Don't clip the scrolled child, and don't paint scrollbars/scrollcorner.
-    // The scrolled frame shouldn't have its own background/border, so we
-    // can just pass aLists directly.
-    mOuter->BuildDisplayListForChild(aBuilder, mScrolledFrame, set);
-
-    bool topLayerIsOpaque = false;
-    if (nsDisplayWrapList* topLayerWrapList =
-            MaybeCreateTopLayerItems(aBuilder, &topLayerIsOpaque)) {
-      if (topLayerIsOpaque) {
-        set.DeleteAll(aBuilder);
-      }
-      set.PositionedDescendants()->AppendToTop(topLayerWrapList);
+      // Don't clip the scrolled child, and don't paint scrollbars/scrollcorner.
+      // The scrolled frame shouldn't have its own background/border, so we
+      // can just pass aLists directly.
+      mOuter->BuildDisplayListForChild(aBuilder, mScrolledFrame, aLists);
     }
 
+    MaybeAddTopLayerItems(aBuilder, aLists);
+
     if (addScrollBars) {
       // Add overlay scrollbars.
-      AppendScrollPartsTo(aBuilder, set, createLayersForScrollbars, true);
+      AppendScrollPartsTo(aBuilder, aLists, createLayersForScrollbars, true);
     }
 
-    set.MoveTo(aLists);
     return;
   }
 
@@ -3965,17 +3957,7 @@ void ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder* aBuilder,
     }
   }
 
-  // Create any required items for the 'top layer' and check if they'll be
-  // opaque over the entire area of the viewport. If they are, then we can
-  // skip building display items for the rest of the page.
-  bool topLayerIsOpaque = false;
-  if (nsDisplayWrapList* topLayerWrapList =
-          MaybeCreateTopLayerItems(aBuilder, &topLayerIsOpaque)) {
-    if (topLayerIsOpaque) {
-      set.DeleteAll(aBuilder);
-    }
-    set.PositionedDescendants()->AppendToTop(topLayerWrapList);
-  }
+  MaybeAddTopLayerItems(aBuilder, set);
 
   if (willBuildAsyncZoomContainer) {
     MOZ_ASSERT(mClipAllDescendants);
@@ -4078,13 +4060,12 @@ void ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder* aBuilder,
   scrolledContent.MoveTo(aLists);
 }
 
-nsDisplayWrapList* ScrollFrameHelper::MaybeCreateTopLayerItems(
-    nsDisplayListBuilder* aBuilder, bool* aIsOpaque) {
+void ScrollFrameHelper::MaybeAddTopLayerItems(nsDisplayListBuilder* aBuilder,
+                                              const nsDisplayListSet& aLists) {
   if (mIsRoot) {
     if (ViewportFrame* viewportFrame = do_QueryFrame(mOuter->GetParent())) {
       nsDisplayList topLayerList;
-      viewportFrame->BuildDisplayListForTopLayer(aBuilder, &topLayerList,
-                                                 aIsOpaque);
+      viewportFrame->BuildDisplayListForTopLayer(aBuilder, &topLayerList);
       if (!topLayerList.IsEmpty()) {
         nsDisplayListBuilder::AutoBuildingDisplayList buildingDisplayList(
             aBuilder, viewportFrame);
@@ -4098,12 +4079,11 @@ nsDisplayWrapList* ScrollFrameHelper::MaybeCreateTopLayerItems(
         if (wrapList) {
           wrapList->SetOverrideZIndex(
               std::numeric_limits<decltype(wrapList->ZIndex())>::max());
-          return wrapList;
+          aLists.PositionedDescendants()->AppendToTop(wrapList);
         }
       }
     }
   }
-  return nullptr;
 }
 
 nsRect ScrollFrameHelper::RestrictToRootDisplayPort(

layout/generic/nsGfxScrollFrame.h

@@ -95,8 +95,8 @@ class ScrollFrameHelper : public nsIReflowCallback {
   // wrapped in the async zoom container, if we're building one.
   // It should not be called with an ASR setter on the stack, as the
   // top-layer items handle setting up their own ASRs.
-  nsDisplayWrapList* MaybeCreateTopLayerItems(nsDisplayListBuilder* aBuilder,
-                                              bool* aIsOpaque);
+  void MaybeAddTopLayerItems(nsDisplayListBuilder* aBuilder,
+                             const nsDisplayListSet& aLists);
 
   void AppendScrollPartsTo(nsDisplayListBuilder* aBuilder,
                            const nsDisplayListSet& aLists, bool aCreateLayer,