Bug 1258851 - Propagate the isScrollbarContainer layer flag to the compositor. r=mattwoodrow

MozReview-Commit-ID: F0U0mNTI9i

--HG--
extra : rebase_source : 43edddd678e7c6d77ddb016c8c2313f1f491a16c

gfx/layers/Layers.cpp

@@ -1963,6 +1963,9 @@ Layer::PrintInfo(std::stringstream& aStream, const char* aPrefix)
   if (Is3DContextLeaf()) {
     aStream << " [is3DContextLeaf]";
   }
+  if (IsScrollbarContainer()) {
+    aStream << " [scrollbar]";
+  }
   if (GetScrollbarDirection() == VERTICAL) {
     aStream << nsPrintfCString(" [vscrollbar=%lld]", GetScrollbarTargetContainerId()).get();
   }

gfx/layers/ipc/LayerTransactionParent.cpp

@@ -361,6 +361,9 @@ LayerTransactionParent::RecvUpdate(InfallibleTArray<Edit>&& cset,
       layer->SetScrollbarData(common.scrollbarTargetContainerId(),
         static_cast<Layer::ScrollDirection>(common.scrollbarDirection()),
         common.scrollbarThumbRatio());
+      if (common.isScrollbarContainer()) {
+        layer->SetIsScrollbarContainer();
+      }
       layer->SetMixBlendMode((gfx::CompositionOp)common.mixBlendMode());
       layer->SetForceIsolatedGroup(common.forceIsolatedGroup());
       if (PLayerParent* maskLayer = common.maskLayerParent()) {

gfx/layers/ipc/LayersMessages.ipdlh

@@ -230,6 +230,7 @@ struct CommonLayerAttributes {
   uint64_t scrollbarTargetContainerId;
   uint32_t scrollbarDirection;
   float scrollbarThumbRatio;
+  bool isScrollbarContainer;
   int8_t mixBlendMode;
   bool forceIsolatedGroup;
   nullable PLayer maskLayer;

gfx/layers/ipc/ShadowLayers.cpp

@@ -834,6 +834,7 @@ ShadowLayerForwarder::EndTransaction(InfallibleTArray<EditReply>* aReplies,
     common.scrollbarTargetContainerId() = mutant->GetScrollbarTargetContainerId();
     common.scrollbarDirection() = mutant->GetScrollbarDirection();
     common.scrollbarThumbRatio() = mutant->GetScrollbarThumbRatio();
+    common.isScrollbarContainer() = mutant->IsScrollbarContainer();
     common.mixBlendMode() = (int8_t)mutant->GetMixBlendMode();
     common.forceIsolatedGroup() = mutant->GetForceIsolatedGroup();
     if (Layer* maskLayer = mutant->GetMaskLayer()) {