Bug 1617179 - Remove IsCurrentlyCheckerboarding. r=botond

IsCurrentlyCheckerboarding can be removed now, as it does the same underlying
computation as "GetCheckerboardMagnitude(...) > 0". The only difference is that
the caller now needs to compute the clipped composition bounds, which is
easy enough to do at the one call site.

Differential Revision: https://phabricator.services.mozilla.com/D67377

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

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -3653,17 +3653,20 @@ bool APZCTreeManager::GetAPZTestData(LayersId aLayersId,
   }
 
   {  // add some additional "current state" into the returned APZTestData
-    RecursiveMutexAutoLock treeLock(
-        mTreeLock);                   // for IsCurrentlyCheckerboarding
-    MutexAutoLock mapLock(mMapLock);  // for mApzcMap
+    MutexAutoLock mapLock(mMapLock);
+
+    ClippedCompositionBoundsMap clippedCompBounds;
     for (const auto& mapping : mApzcMap) {
       if (mapping.first.mLayersId != aLayersId) {
         continue;
       }
+
+      ParentLayerRect clippedBounds = ComputeClippedCompositionBounds(
+          mapLock, clippedCompBounds, mapping.first);
       AsyncPanZoomController* apzc = mapping.second.apzc;
       std::string viewId = std::to_string(mapping.first.mScrollId);
       std::string apzcState;
-      if (apzc->IsCurrentlyCheckerboarding()) {
+      if (apzc->GetCheckerboardMagnitude(clippedBounds)) {
         apzcState += "checkerboarding,";
       }
       aOutData->RecordAdditionalData(viewId, apzcState);

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -4327,78 +4327,6 @@ CSSRect AsyncPanZoomController::GetVisibleRect(
   return visible;
 }
 
-ParentLayerRect AsyncPanZoomController::RecursivelyClipCompBounds(
-    const ParentLayerRect& aChildCompBounds) const {
-  // The childCompBounds is in the ParentLayer space of a child layer, which
-  // is the Layer space of this layer, so we can cast it.
-  LayerRect compBoundsInLayerSpace = ViewAs<LayerPixel>(
-      aChildCompBounds, PixelCastJustification::MovingDownToChildren);
-
-  // Apply the async transform from this layer and then clip with this
-  // layer's composition bounds.
-  AsyncTransform appliesToLayer =
-      GetCurrentAsyncTransform(AsyncPanZoomController::eForCompositing);
-  ParentLayerRect compBoundsInParentSpace =
-      (compBoundsInLayerSpace * appliesToLayer.mScale) +
-      appliesToLayer.mTranslation;
-
-  {  // hold lock while reading Metrics()
-    RecursiveMutexAutoLock lock(mRecursiveMutex);
-    compBoundsInParentSpace =
-        compBoundsInParentSpace.Intersect(Metrics().GetCompositionBounds());
-  }
-
-  // Recurse up the tree
-  if (mParent) {
-    // Make sure we're not holding our lock when we do this, to be extra safe.
-    mRecursiveMutex.AssertNotCurrentThreadIn();
-    compBoundsInParentSpace =
-        mParent->RecursivelyClipCompBounds(compBoundsInParentSpace);
-  }
-
-  // Undo async transformation from above to produce return value in the same
-  // coordinate space as the input parameter.
-  compBoundsInLayerSpace =
-      (compBoundsInParentSpace - appliesToLayer.mTranslation) /
-      appliesToLayer.mScale;
-  return ViewAs<ParentLayerPixel>(compBoundsInLayerSpace,
-                                  PixelCastJustification::MovingDownToChildren);
-}
-
-CSSRect AsyncPanZoomController::GetRecursivelyVisibleRect() const {
-  CSSRect visible;
-  ParentLayerRect compBounds;
-  CSSToParentLayerScale2D zoom;
-
-  {  // scope mutex
-    RecursiveMutexAutoLock lock(mRecursiveMutex);
-    visible = GetVisibleRect(lock);  // relative to scrolled frame origin
-    compBounds = Metrics().GetCompositionBounds();
-    zoom = Metrics().GetZoom();
-  }
-
-  if (mParent) {
-    // compBounds and clippedCompBounds are relative to the layer tree origin
-    ParentLayerRect clippedCompBounds =
-        mParent->RecursivelyClipCompBounds(compBounds);
-
-    // the "*RelativeToItself*" variables are relative to the comp bounds origin
-    ParentLayerRect visiblePartOfCompBoundsRelativeToItself =
-        clippedCompBounds - compBounds.TopLeft();
-
-    CSSRect visiblePartOfCompBoundsRelativeToItselfInCssSpace =
-        (visiblePartOfCompBoundsRelativeToItself / zoom);
-
-    // this one is relative to the scrolled frame origin, same as `visible`
-    CSSRect visiblePartOfCompBoundsInCssSpace =
-        visiblePartOfCompBoundsRelativeToItselfInCssSpace + visible.TopLeft();
-
-    visible = visible.Intersect(visiblePartOfCompBoundsInCssSpace);
-  }
-
-  return visible;
-}
-
 uint32_t AsyncPanZoomController::GetCheckerboardMagnitude(
     const ParentLayerRect& aClippedCompositionBounds) const {
   RecursiveMutexAutoLock lock(mRecursiveMutex);
@@ -4505,26 +4433,6 @@ void AsyncPanZoomController::FlushActiveCheckerboardReport() {
   UpdateCheckerboardEvent(lock, 0);
 }
 
-bool AsyncPanZoomController::IsCurrentlyCheckerboarding() const {
-  CSSRect painted;
-  {  // scope lock
-    RecursiveMutexAutoLock lock(mRecursiveMutex);
-    painted = mLastContentPaintMetrics.GetDisplayPort() +
-              mLastContentPaintMetrics.GetScrollOffset();
-  }
-
-  painted.Inflate(CSSMargin::FromAppUnits(
-      nsMargin(1, 1, 1, 1)));  // fuzz for rounding error
-  CSSRect visible = GetRecursivelyVisibleRect();
-  if (visible.IsEmpty() || painted.Contains(visible)) {
-    return false;
-  }
-  APZC_LOG_FM(Metrics(),
-              "%p is currently checkerboarding (painted %s visible %s)", this,
-              Stringify(painted).c_str(), Stringify(visible).c_str());
-  return true;
-}
-
 void AsyncPanZoomController::NotifyLayersUpdated(
     const ScrollMetadata& aScrollMetadata, bool aIsFirstPaint,
     bool aThisLayerTreeUpdated) {

gfx/layers/apz/src/AsyncPanZoomController.h

@@ -333,14 +333,6 @@ class AsyncPanZoomController {
    */
   void FlushActiveCheckerboardReport();
 
-  /**
-   * Returns whether or not the APZC is currently in a state of checkerboarding.
-   * This is a simple computation based on the last-painted content and whether
-   * the async transform has pushed it so far that it doesn't fully contain the
-   * composition bounds.
-   */
-  bool IsCurrentlyCheckerboarding() const;
-
   /**
    * Recalculates the displayport. Ideally, this should paint an area bigger
    * than the composite-to dimensions so that when you scroll down, you don't
@@ -1220,25 +1212,6 @@ class AsyncPanZoomController {
    * CSS pixels. The caller must have acquired the mRecursiveMutex lock.
    */
   CSSRect GetVisibleRect(const RecursiveMutexAutoLock& aProofOfLock) const;
-  /**
-   * This returns the composition bounds of this APZC, but accounting for
-   * ancestor state. It's possible to have a scrollable frame with giant
-   * composition bounds nested inside a scrollable frame with smaller
-   * composition bounds, or even scrolled out of view entirely by an
-   * ancestor scrollable frame. This function accounts for those possibilities,
-   * by walking up to the root of the tree and clipping the composition bounds
-   * needed by the state of ancestor scrollframes. The returned value is
-   * in the same coordinate space as the composition bounds, and is guaranteed
-   * to be contained by the composition bounds.
-   */
-  ParentLayerRect RecursivelyClipCompBounds(
-      const ParentLayerRect& aChildCompBounds) const;
-  /**
-   * Similar to GetVisibleRect, but this accounts for ancestor APZC's
-   * composition bounds as well. Conceptually this is the intersection of
-   * GetVisibleRect() with RecursivelyClipCompBounds().
-   */
-  CSSRect GetRecursivelyVisibleRect() const;
 
  private:
   friend class AutoApplyAsyncTestAttributes;