Bug 1610731 - Add plumbing for sticky data. r=botond

This patch is pretty uninteresting, just building the pipe to move data
from the main-thread to APZ.

Differential Revision: https://phabricator.services.mozilla.com/D69555

--HG--
extra : moz-landing-system : lando

gfx/ipc/GfxMessageUtils.h

@@ -569,6 +569,31 @@ struct ParamTraits<mozilla::gfx::RectTyped<T>> {
   }
 };
 
+template <class T>
+struct ParamTraits<mozilla::gfx::RectAbsoluteTyped<T>> {
+  typedef mozilla::gfx::RectAbsoluteTyped<T> paramType;
+
+  static void Write(Message* msg, const paramType& param) {
+    WriteParam(msg, param.Left());
+    WriteParam(msg, param.Right());
+    WriteParam(msg, param.Top());
+    WriteParam(msg, param.Bottom());
+  }
+
+  static bool Read(const Message* msg, PickleIterator* iter,
+                   paramType* result) {
+    auto l = result->Left();
+    auto r = result->Right();
+    auto t = result->Top();
+    auto b = result->Bottom();
+
+    bool retVal = (ReadParam(msg, iter, &l) && ReadParam(msg, iter, &r) &&
+                   ReadParam(msg, iter, &t) && ReadParam(msg, iter, &b));
+    result->SetBox(l, r, t, b);
+    return retVal;
+  }
+};
+
 template <class T>
 struct ParamTraits<mozilla::gfx::IntRectTyped<T>> {
   typedef mozilla::gfx::IntRectTyped<T> paramType;

gfx/layers/LayerMetricsWrapper.h

@@ -455,6 +455,14 @@ class MOZ_STACK_CLASS LayerMetricsWrapper final {
     return empty;
   }
 
+  Maybe<uint64_t> GetStickyPositionAnimationId() const {
+    MOZ_ASSERT(IsValid());
+    // This function is only really needed for template-compatibility with
+    // WebRenderScrollDataWrapper. Although it will be called, the return
+    // value is not used.
+    return Nothing();
+  }
+
   Maybe<uint64_t> GetZoomAnimationId() const {
     MOZ_ASSERT(IsValid());
     // This function is only really needed for template-compatibility with

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -152,6 +152,7 @@ struct APZCTreeManager::TreeBuildingState {
   // a layers update, and then moved into APZCTreeManager.
   std::vector<FixedPositionInfo> mFixedPositionInfo;
   std::vector<RootScrollbarInfo> mRootScrollbarInfo;
+  std::vector<StickyPositionInfo> mStickyPositionInfo;
 };
 
 class APZCTreeManager::CheckerboardFlushObserver : public nsIObserver {
@@ -484,6 +485,12 @@ APZCTreeManager::UpdateHitTestingTreeImpl(const ScrollNode& aRoot,
                 *(node->GetFixedPositionAnimationId()),
                 node->GetFixedPosSides());
           }
+          // GetStickyPositionAnimationId is only set when webrender is enabled.
+          if (node->GetStickyPositionAnimationId().isSome()) {
+            state.mStickyPositionInfo.emplace_back(
+                *(node->GetStickyPositionAnimationId()),
+                node->GetFixedPosSides());
+          }
           if (apzc && node->IsPrimaryHolder()) {
             state.mScrollTargets[apzc->GetGuid()] = node;
           }
@@ -631,6 +638,7 @@ APZCTreeManager::UpdateHitTestingTreeImpl(const ScrollNode& aRoot,
 
     mRootScrollbarInfo = std::move(state.mRootScrollbarInfo);
     mFixedPositionInfo = std::move(state.mFixedPositionInfo);
+    mStickyPositionInfo = std::move(state.mStickyPositionInfo);
   }
 
   for (size_t i = 0; i < state.mNodesToDestroy.Length(); i++) {
@@ -1176,7 +1184,8 @@ HitTestingTreeNode* APZCTreeManager::PrepareNodeForLayer(
                           aLayer.GetFixedPositionAnimationId());
     node->SetStickyPosData(aLayer.GetStickyScrollContainerId(),
                            aLayer.GetStickyScrollRangeOuter(),
-                           aLayer.GetStickyScrollRangeInner());
+                           aLayer.GetStickyScrollRangeInner(),
+                           aLayer.GetStickyPositionAnimationId());
     return node;
   }
 
@@ -1405,7 +1414,8 @@ HitTestingTreeNode* APZCTreeManager::PrepareNodeForLayer(
                         aLayer.GetFixedPositionAnimationId());
   node->SetStickyPosData(aLayer.GetStickyScrollContainerId(),
                          aLayer.GetStickyScrollRangeOuter(),
-                         aLayer.GetStickyScrollRangeInner());
+                         aLayer.GetStickyScrollRangeInner(),
+                         aLayer.GetStickyPositionAnimationId());
   return node;
 }
 

gfx/layers/apz/src/APZCTreeManager.h

@@ -816,8 +816,8 @@ class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
    */
   bool mUsingAsyncZoomContainer;
 
-  /** A lock that protects mApzcMap, mScrollThumbInfo, mRootScrollbarInfo, and
+  /** A lock that protects mApzcMap, mScrollThumbInfo, mRootScrollbarInfo,
-   * mFixedPositionInfo.
+   * mFixedPositionInfo, and mStickyPositionInfo.
    */
   mutable mozilla::Mutex mMapLock;
 
@@ -933,6 +933,32 @@ class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
    */
   std::vector<FixedPositionInfo> mFixedPositionInfo;
 
+  /**
+   * A helper structure to store all the information needed to compute the
+   * async transform for a sticky position element on the sampler thread.
+   */
+  struct StickyPositionInfo {
+    uint64_t mStickyPositionAnimationId;
+    SideBits mFixedPosSides;
+
+    StickyPositionInfo(const uint64_t& aStickyPositionAnimationId,
+                       const SideBits aFixedPosSides)
+        : mStickyPositionAnimationId(aStickyPositionAnimationId),
+          mFixedPosSides(aFixedPosSides) {}
+  };
+  /**
+   * If this APZCTreeManager is being used with WebRender, this vector gets
+   * populated during a layers update. It holds a package of information needed
+   * to compute and set the async transforms on sticky position content. This
+   * information is extracted from the HitTestingTreeNodes for the WebRender
+   * case because accessing the HitTestingTreeNodes requires holding the tree
+   * lock which we cannot do on the WR sampler thread. mStickyPositionInfo,
+   * however, can be accessed while just holding the mMapLock which is safe to
+   * do on the sampler thread. mMapLock must be acquired while accessing or
+   * modifying mStickyPositionInfo.
+   */
+  std::vector<StickyPositionInfo> mStickyPositionInfo;
+
   /* Holds the zoom constraints for scrollable layers, as determined by the
    * the main-thread gecko code. This can only be accessed on the updater
    * thread. */

gfx/layers/apz/src/HitTestingTreeNode.cpp

@@ -177,10 +177,12 @@ void HitTestingTreeNode::SetPrevSibling(HitTestingTreeNode* aSibling) {
 void HitTestingTreeNode::SetStickyPosData(
     ScrollableLayerGuid::ViewID aStickyPosTarget,
     const LayerRectAbsolute& aScrollRangeOuter,
-    const LayerRectAbsolute& aScrollRangeInner) {
+    const LayerRectAbsolute& aScrollRangeInner,
+    const Maybe<uint64_t>& aStickyPositionAnimationId) {
   mStickyPosTarget = aStickyPosTarget;
   mStickyScrollRangeOuter = aScrollRangeOuter;
   mStickyScrollRangeInner = aScrollRangeInner;
+  mStickyPositionAnimationId = aStickyPositionAnimationId;
 }
 
 ScrollableLayerGuid::ViewID HitTestingTreeNode::GetStickyPosTarget() const {
@@ -195,6 +197,10 @@ const LayerRectAbsolute& HitTestingTreeNode::GetStickyScrollRangeInner() const {
   return mStickyScrollRangeInner;
 }
 
+Maybe<uint64_t> HitTestingTreeNode::GetStickyPositionAnimationId() const {
+  return mStickyPositionAnimationId;
+}
+
 void HitTestingTreeNode::MakeRoot() {
   mParent = nullptr;
 

gfx/layers/apz/src/HitTestingTreeNode.h

@@ -136,10 +136,12 @@ class HitTestingTreeNode {
   /* Sticky pos info */
   void SetStickyPosData(ScrollableLayerGuid::ViewID aStickyPosTarget,
                         const LayerRectAbsolute& aScrollRangeOuter,
-                        const LayerRectAbsolute& aScrollRangeInner);
+                        const LayerRectAbsolute& aScrollRangeInner,
+                        const Maybe<uint64_t>& aStickyPositionAnimationId);
   ScrollableLayerGuid::ViewID GetStickyPosTarget() const;
   const LayerRectAbsolute& GetStickyScrollRangeOuter() const;
   const LayerRectAbsolute& GetStickyScrollRangeInner() const;
+  Maybe<uint64_t> GetStickyPositionAnimationId() const;
 
   /* Convert |aPoint| into the LayerPixel space for the layer corresponding to
    * this node. |aTransform| is the complete (content + async) transform for
@@ -205,6 +207,9 @@ class HitTestingTreeNode {
   ScrollableLayerGuid::ViewID mStickyPosTarget;
   LayerRectAbsolute mStickyScrollRangeOuter;
   LayerRectAbsolute mStickyScrollRangeInner;
+  // This is only set if WebRender is enabled. It holds the animation id that
+  // we use to adjust sticky position content for the toolbar.
+  Maybe<uint64_t> mStickyPositionAnimationId;
 
   /* Let {L,M} be the {layer, scrollable metrics} pair that this node
    * corresponds to in the layer tree. mEventRegions contains the event regions

gfx/layers/wr/WebRenderScrollData.cpp

@@ -23,6 +23,7 @@ WebRenderLayerScrollData::WebRenderLayerScrollData()
       mEventRegionsOverride(EventRegionsOverride::NoOverride),
       mFixedPositionSides(mozilla::SideBits::eNone),
       mFixedPosScrollContainerId(ScrollableLayerGuid::NULL_SCROLL_ID),
+      mStickyPosScrollContainerId(ScrollableLayerGuid::NULL_SCROLL_ID),
       mRenderRoot(wr::RenderRoot::Default) {}
 
 WebRenderLayerScrollData::~WebRenderLayerScrollData() = default;

gfx/layers/wr/WebRenderScrollData.h

@@ -124,6 +124,34 @@ class WebRenderLayerScrollData final {
     return mFixedPosScrollContainerId;
   }
 
+  void SetStickyPositionScrollContainerId(ScrollableLayerGuid::ViewID aId) {
+    mStickyPosScrollContainerId = aId;
+  }
+  ScrollableLayerGuid::ViewID GetStickyPositionScrollContainerId() const {
+    return mStickyPosScrollContainerId;
+  }
+
+  void SetStickyScrollRangeOuter(const LayerRectAbsolute& scrollRange) {
+    mStickyScrollRangeOuter = scrollRange;
+  }
+  const LayerRectAbsolute& GetStickyScrollRangeOuter() const {
+    return mStickyScrollRangeOuter;
+  }
+
+  void SetStickyScrollRangeInner(const LayerRectAbsolute& scrollRange) {
+    mStickyScrollRangeInner = scrollRange;
+  }
+  const LayerRectAbsolute& GetStickyScrollRangeInner() const {
+    return mStickyScrollRangeInner;
+  }
+
+  void SetStickyPositionAnimationId(const uint64_t& aId) {
+    mStickyPositionAnimationId = Some(aId);
+  }
+  Maybe<uint64_t> GetStickyPositionAnimationId() const {
+    return mStickyPositionAnimationId;
+  }
+
   wr::RenderRoot GetRenderRoot() { return mRenderRoot; }
 
   void SetZoomAnimationId(const uint64_t& aId) { mZoomAnimationId = Some(aId); }
@@ -171,6 +199,10 @@ class WebRenderLayerScrollData final {
   Maybe<uint64_t> mFixedPositionAnimationId;
   SideBits mFixedPositionSides;
   ScrollableLayerGuid::ViewID mFixedPosScrollContainerId;
+  ScrollableLayerGuid::ViewID mStickyPosScrollContainerId;
+  LayerRectAbsolute mStickyScrollRangeOuter;
+  LayerRectAbsolute mStickyScrollRangeInner;
+  Maybe<uint64_t> mStickyPositionAnimationId;
   wr::RenderRoot mRenderRoot;
   Maybe<uint64_t> mZoomAnimationId;
   Maybe<ScrollableLayerGuid::ViewID> mAsyncZoomContainerId;
@@ -274,6 +306,10 @@ struct ParamTraits<mozilla::layers::WebRenderLayerScrollData> {
     WriteParam(aMsg, aParam.mFixedPositionAnimationId);
     WriteParam(aMsg, aParam.mFixedPositionSides);
     WriteParam(aMsg, aParam.mFixedPosScrollContainerId);
+    WriteParam(aMsg, aParam.mStickyPosScrollContainerId);
+    WriteParam(aMsg, aParam.mStickyScrollRangeOuter);
+    WriteParam(aMsg, aParam.mStickyScrollRangeInner);
+    WriteParam(aMsg, aParam.mStickyPositionAnimationId);
     WriteParam(aMsg, aParam.mRenderRoot);
     WriteParam(aMsg, aParam.mZoomAnimationId);
     WriteParam(aMsg, aParam.mAsyncZoomContainerId);
@@ -295,6 +331,10 @@ struct ParamTraits<mozilla::layers::WebRenderLayerScrollData> {
            ReadParam(aMsg, aIter, &aResult->mFixedPositionAnimationId) &&
            ReadParam(aMsg, aIter, &aResult->mFixedPositionSides) &&
            ReadParam(aMsg, aIter, &aResult->mFixedPosScrollContainerId) &&
+           ReadParam(aMsg, aIter, &aResult->mStickyPosScrollContainerId) &&
+           ReadParam(aMsg, aIter, &aResult->mStickyScrollRangeOuter) &&
+           ReadParam(aMsg, aIter, &aResult->mStickyScrollRangeInner) &&
+           ReadParam(aMsg, aIter, &aResult->mStickyPositionAnimationId) &&
            ReadParam(aMsg, aIter, &aResult->mRenderRoot) &&
            ReadParam(aMsg, aIter, &aResult->mZoomAnimationId) &&
            ReadParam(aMsg, aIter, &aResult->mAsyncZoomContainerId);

gfx/layers/wr/WebRenderScrollDataWrapper.h

@@ -332,23 +332,41 @@ class MOZ_STACK_CLASS WebRenderScrollDataWrapper final {
   ScrollableLayerGuid::ViewID GetStickyScrollContainerId() const {
     MOZ_ASSERT(IsValid());
 
-    // TODO: Bug 1610731 Implement this for WebRender.
+    if (AtBottomLayer()) {
+      return mLayer->GetStickyPositionScrollContainerId();
+    }
     return ScrollableLayerGuid::NULL_SCROLL_ID;
   }
 
   const LayerRectAbsolute& GetStickyScrollRangeOuter() const {
     MOZ_ASSERT(IsValid());
-    static const LayerRectAbsolute dummy;
 
-    // TODO: Bug 1610731 Implement this for WebRender.
+    if (AtBottomLayer()) {
-    return dummy;
+      return mLayer->GetStickyScrollRangeOuter();
+    }
+
+    static const LayerRectAbsolute empty;
+    return empty;
   }
+
   const LayerRectAbsolute& GetStickyScrollRangeInner() const {
     MOZ_ASSERT(IsValid());
-    static const LayerRectAbsolute dummy;
 
-    // TODO: Bug 1610731 Implement this for WebRender.
+    if (AtBottomLayer()) {
-    return dummy;
+      return mLayer->GetStickyScrollRangeInner();
+    }
+
+    static const LayerRectAbsolute empty;
+    return empty;
+  }
+
+  Maybe<uint64_t> GetStickyPositionAnimationId() const {
+    MOZ_ASSERT(IsValid());
+
+    if (AtBottomLayer()) {
+      return mLayer->GetStickyPositionAnimationId();
+    }
+    return Nothing();
   }
 
   Maybe<uint64_t> GetZoomAnimationId() const {