Bug 1753019 - Adjust sticky position elements for the dynamic toolbar. r=botond

Use the animation id from the stacking context to find the hit-testing tree node
for hit tests of elements that are sticky positioned. Then use this hit-testing
tree node reference to apply APZ transforms if the sticky positioned element is
stuck to the root content.

Differential Revision: https://phabricator.services.mozilla.com/D150047

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -2039,6 +2039,17 @@ void APZCTreeManager::ProcessTouchInput(InputHandlingState& aState,
           touchData.mScreenPoint -= RoundedToInt(apz::ComputeFixedMarginsOffset(
               GetCompositorFixedLayerMargins(lock),
               mTouchBlockHitResult.mFixedPosSides, mGeckoFixedLayerMargins));
+        } else if (mTouchBlockHitResult.mNode &&
+                   mTouchBlockHitResult.mNode->GetStickyPositionAnimationId()) {
+          SideBits sideBits = SideBits::eNone;
+          {
+            RecursiveMutexAutoLock lock(mTreeLock);
+            sideBits =
+                SidesStuckToRootContent(mTouchBlockHitResult.mNode.Get(lock));
+          }
+          MutexAutoLock lock(mMapLock);
+          touchData.mScreenPoint -= RoundedToInt(apz::ComputeFixedMarginsOffset(
+              GetCompositorFixedLayerMargins(lock), sideBits, ScreenMargin()));
         }
       }
     }
@@ -3239,6 +3250,14 @@ Maybe<ScreenIntPoint> APZCTreeManager::ConvertToGecko(
       *geckoPoint -= RoundedToInt(apz::ComputeFixedMarginsOffset(
           GetCompositorFixedLayerMargins(mapLock),
           mTouchBlockHitResult.mFixedPosSides, mGeckoFixedLayerMargins));
+    } else if (mTouchBlockHitResult.mNode &&
+               mTouchBlockHitResult.mNode->GetStickyPositionAnimationId()) {
+      SideBits sideBits =
+          SidesStuckToRootContent(mTouchBlockHitResult.mNode.Get(lock));
+
+      MutexAutoLock mapLock(mMapLock);
+      *geckoPoint -= RoundedToInt(apz::ComputeFixedMarginsOffset(
+          GetCompositorFixedLayerMargins(mapLock), sideBits, ScreenMargin()));
     }
   }
   return geckoPoint;

gfx/layers/apz/src/WRHitTester.cpp

@@ -207,13 +207,15 @@ IAPZHitTester::HitTestResult WRHitTester::GetAPZCAtPoint(
 
     positionedNode = BreadthFirstSearch<ReverseIterator>(
         GetRootNode(), [&](HitTestingTreeNode* aNode) {
-          return aNode->GetFixedPositionAnimationId() == animationId;
+          return (aNode->GetFixedPositionAnimationId() == animationId ||
+                  aNode->GetStickyPositionAnimationId() == animationId);
         });
 
     if (positionedNode) {
       MOZ_ASSERT(positionedNode->GetLayersId() == chosenResult->mLayersId,
                  "Found node layers id does not match the hit result");
-      MOZ_ASSERT(positionedNode->GetFixedPositionAnimationId().isSome(),
+      MOZ_ASSERT((positionedNode->GetFixedPositionAnimationId().isSome() ||
+                  positionedNode->GetStickyPositionAnimationId().isSome()),
                  "A a matching fixed/sticky position node should be found");
       InitializeHitTestingTreeNodeAutoLock(hit.mNode, aProofOfTreeLock,
                                            positionedNode);

layout/painting/nsDisplayList.cpp

@@ -5250,7 +5250,8 @@ bool nsDisplayOwnLayer::CreateWebRenderCommands(
                    (IsScrollThumbLayer() || IsZoomingLayer() ||
                     (IsFixedPositionLayer() &&
                      ShouldFixedAndStickyContentGetAnimationIds()) ||
-                    (IsStickyPositionLayer() && HasDynamicToolbar()) ||
+                    (IsStickyPositionLayer() &&
+                     ShouldFixedAndStickyContentGetAnimationIds()) ||
                     (IsRootScrollbarContainer() && HasDynamicToolbar()));
 
   if (needsProp) {
@@ -5279,7 +5280,8 @@ bool nsDisplayOwnLayer::CreateWebRenderCommands(
   if (IsZoomingLayer() ||
       ((IsFixedPositionLayer() &&
         ShouldFixedAndStickyContentGetAnimationIds()) ||
-       (IsStickyPositionLayer() && HasDynamicToolbar()) ||
+       (IsStickyPositionLayer() &&
+        ShouldFixedAndStickyContentGetAnimationIds()) ||
        (IsRootScrollbarContainer() && HasDynamicToolbar()))) {
     params.is_2d_scale_translation = true;
     params.should_snap = true;
@@ -5299,7 +5301,8 @@ bool nsDisplayOwnLayer::UpdateScrollData(WebRenderScrollData* aData,
       (IsScrollThumbLayer() || IsScrollbarContainer() || IsZoomingLayer() ||
        (IsFixedPositionLayer() &&
         ShouldFixedAndStickyContentGetAnimationIds()) ||
-       (IsStickyPositionLayer() && HasDynamicToolbar()));
+       (IsStickyPositionLayer() &&
+        ShouldFixedAndStickyContentGetAnimationIds()));
 
   if (!isRelevantToApz) {
     return false;
@@ -5319,7 +5322,7 @@ bool nsDisplayOwnLayer::UpdateScrollData(WebRenderScrollData* aData,
     return true;
   }
 
-  if (IsStickyPositionLayer() && HasDynamicToolbar()) {
+  if (IsStickyPositionLayer() && ShouldFixedAndStickyContentGetAnimationIds()) {
     aLayerData->SetStickyPositionAnimationId(mWrAnimationId);
     return true;
   }