Bug 1324591 - Store PrerenderDecision in nsDisplayTransform. r=botond

Depends on D75728

Differential Revision: https://phabricator.services.mozilla.com/D75729

layout/generic/nsFrame.cpp

@@ -3260,17 +3260,15 @@ void nsIFrame::BuildDisplayListForStackingContext(
   aBuilder->SetContainsBackdropFilter(false);
 
   nsRect visibleRectOutsideTransform = visibleRect;
-  bool allowAsyncAnimation = false;
+  nsDisplayTransform::PrerenderInfo prerenderInfo;
   bool inTransform = aBuilder->IsInTransform();
   if (isTransformed) {
-    nsDisplayTransform::PrerenderInfo decision =
-        nsDisplayTransform::ShouldPrerenderTransformedContent(aBuilder, this,
-                                                              &dirtyRect);
+    prerenderInfo = nsDisplayTransform::ShouldPrerenderTransformedContent(
+        aBuilder, this, &dirtyRect);
 
-    switch (decision.mDecision) {
+    switch (prerenderInfo.mDecision) {
       case nsDisplayTransform::PrerenderDecision::Full:
       case nsDisplayTransform::PrerenderDecision::Partial:
-        allowAsyncAnimation = true;
         visibleRect = dirtyRect;
         break;
       case nsDisplayTransform::PrerenderDecision::No: {
@@ -3278,7 +3276,7 @@ void nsIFrame::BuildDisplayListForStackingContext(
         // then we want disable async animations for the rest of the preserve-3d
         // (especially ancestors).
         if ((extend3DContext || combines3DTransformWithAncestors) &&
-            decision.mHasAnimations) {
+            prerenderInfo.mHasAnimations) {
           aBuilder->SavePreserves3DAllowAsyncAnimation(false);
         }
 
@@ -3768,14 +3766,15 @@ void nsIFrame::BuildDisplayListForStackingContext(
     // Alternatively we could not block animations for later siblings, and only
     // block them for ancestors of a blocked one.
     if ((extend3DContext || combines3DTransformWithAncestors) &&
-        allowAsyncAnimation) {
+        prerenderInfo.CanUseAsyncAnimations() &&
+        !aBuilder->GetPreserves3DAllowAsyncAnimation()) {
       // aBuilder->GetPreserves3DAllowAsyncAnimation() means the inner or
       // previous silbing frames are allowed/disallowed for async animations.
-      allowAsyncAnimation = aBuilder->GetPreserves3DAllowAsyncAnimation();
+      prerenderInfo.mDecision = nsDisplayTransform::PrerenderDecision::No;
     }
 
     nsDisplayTransform* transformItem = MakeDisplayItem<nsDisplayTransform>(
-        aBuilder, this, &resultList, visibleRect, allowAsyncAnimation);
+        aBuilder, this, &resultList, visibleRect, prerenderInfo.mDecision);
     if (transformItem) {
       resultList.AppendToTop(transformItem);
       ct.TrackContainer(transformItem);

layout/painting/nsDisplayList.cpp

@@ -7287,8 +7287,8 @@ nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
       mAnimatedGeometryRootForChildren(mAnimatedGeometryRoot),
       mAnimatedGeometryRootForScrollMetadata(mAnimatedGeometryRoot),
       mChildrenBuildingRect(aChildrenBuildingRect),
-      mIsTransformSeparator(true),
-      mAllowAsyncAnimation(false) {
+      mPrerenderDecision(PrerenderDecision::No),
+      mIsTransformSeparator(true) {
   MOZ_COUNT_CTOR(nsDisplayTransform);
   MOZ_ASSERT(aFrame, "Must have a frame!");
   Init(aBuilder, aList);
@@ -7297,14 +7297,14 @@ nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
 nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
                                        nsIFrame* aFrame, nsDisplayList* aList,
                                        const nsRect& aChildrenBuildingRect,
-                                       bool aAllowAsyncAnimation)
+                                       PrerenderDecision aPrerenderDecision)
     : nsDisplayHitTestInfoBase(aBuilder, aFrame),
       mTransformGetter(nullptr),
       mAnimatedGeometryRootForChildren(mAnimatedGeometryRoot),
       mAnimatedGeometryRootForScrollMetadata(mAnimatedGeometryRoot),
       mChildrenBuildingRect(aChildrenBuildingRect),
-      mIsTransformSeparator(false),
-      mAllowAsyncAnimation(aAllowAsyncAnimation) {
+      mPrerenderDecision(aPrerenderDecision),
+      mIsTransformSeparator(false) {
   MOZ_COUNT_CTOR(nsDisplayTransform);
   MOZ_ASSERT(aFrame, "Must have a frame!");
   SetReferenceFrameToAncestor(aBuilder);
@@ -7320,8 +7320,8 @@ nsDisplayTransform::nsDisplayTransform(
       mAnimatedGeometryRootForChildren(mAnimatedGeometryRoot),
       mAnimatedGeometryRootForScrollMetadata(mAnimatedGeometryRoot),
       mChildrenBuildingRect(aChildrenBuildingRect),
-      mIsTransformSeparator(false),
-      mAllowAsyncAnimation(false) {
+      mPrerenderDecision(PrerenderDecision::No),
+      mIsTransformSeparator(false) {
   MOZ_COUNT_CTOR(nsDisplayTransform);
   MOZ_ASSERT(aFrame, "Must have a frame!");
   Init(aBuilder, aList);
@@ -7640,7 +7640,7 @@ bool nsDisplayOpacity::CanUseAsyncAnimations(nsDisplayListBuilder* aBuilder) {
 }
 
 bool nsDisplayTransform::CanUseAsyncAnimations(nsDisplayListBuilder* aBuilder) {
-  return mAllowAsyncAnimation;
+  return mPrerenderDecision != PrerenderDecision::No;
 }
 
 bool nsDisplayBackgroundColor::CanUseAsyncAnimations(
@@ -8044,7 +8044,7 @@ already_AddRefed<Layer> nsDisplayTransform::BuildLayer(
                                ~Layer::CONTENT_EXTEND_3D_CONTEXT);
   }
 
-  if (mAllowAsyncAnimation) {
+  if (CanUseAsyncAnimations(aBuilder)) {
     mFrame->SetProperty(nsIFrame::RefusedAsyncAnimationProperty(), false);
   }
 
@@ -8054,7 +8054,7 @@ already_AddRefed<Layer> nsDisplayTransform::BuildLayer(
         container, aBuilder, this, mFrame, GetType());
   }
 
-  if (mAllowAsyncAnimation && MayBeAnimated(aBuilder)) {
+  if (CanUseAsyncAnimations(aBuilder) && MayBeAnimated(aBuilder)) {
     // Only allow async updates to the transform if we're an animated layer,
     // since that's what triggers us to set the correct AGR in the constructor
     // and makes sure FrameLayerBuilder won't compute occlusions for this layer.
@@ -8531,7 +8531,19 @@ void nsDisplayTransform::WriteDebugInfo(std::stringstream& aStream) {
     aStream << " combines-3d-with-ancestors";
   }
 
-  aStream << " allowAsync(" << (mAllowAsyncAnimation ? "true" : "false") << ")";
+  aStream << " prerender(";
+  switch (mPrerenderDecision) {
+    case PrerenderDecision::No:
+      aStream << "no";
+      break;
+    case PrerenderDecision::Partial:
+      aStream << "partial";
+      break;
+    case PrerenderDecision::Full:
+      aStream << "full";
+      break;
+  }
+  aStream << ")";
   aStream << " childrenBuildingRect" << mChildrenBuildingRect;
 }
 

layout/painting/nsDisplayList.h

@@ -6727,7 +6727,7 @@ class nsDisplayTransform : public nsDisplayHitTestInfoBase {
   using TransformReferenceBox = nsStyleTransformMatrix::TransformReferenceBox;
 
  public:
-  enum class PrerenderDecision { No, Full, Partial };
+  enum class PrerenderDecision : uint8_t { No, Full, Partial };
 
   /**
    * Returns a matrix (in pixels) for the current frame. The matrix should be
@@ -6747,7 +6747,7 @@ class nsDisplayTransform : public nsDisplayHitTestInfoBase {
 
   nsDisplayTransform(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                      nsDisplayList* aList, const nsRect& aChildrenBuildingRect,
-                     bool aAllowAsyncAnimation);
+                     PrerenderDecision aPrerenderDecision);
 
   nsDisplayTransform(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                      nsDisplayList* aList, const nsRect& aChildrenBuildingRect,
@@ -7006,6 +7006,9 @@ class nsDisplayTransform : public nsDisplayHitTestInfoBase {
       float aAppUnitsPerPixel);
 
   struct PrerenderInfo {
+    bool CanUseAsyncAnimations() const {
+      return mDecision != PrerenderDecision::No && mHasAnimations;
+    }
     PrerenderDecision mDecision = PrerenderDecision::No;
     bool mHasAnimations = true;
   };
@@ -7082,6 +7085,7 @@ class nsDisplayTransform : public nsDisplayHitTestInfoBase {
   nsRect mChildBounds;
   // The transformed bounds of this display item.
   nsRect mBounds;
+  PrerenderDecision mPrerenderDecision : 8;
   // This item is a separator between 3D rendering contexts, and
   // mTransform have been presetted by the constructor.
   // This also forces us not to extend the 3D context.  Since we don't create a
@@ -7089,11 +7093,9 @@ class nsDisplayTransform : public nsDisplayHitTestInfoBase {
   // context, the transform items of a child preserves3d context may extend the
   // parent context unintendedly if the root of the child preserves3d context
   // doesn't create a transform item.
-  bool mIsTransformSeparator;
-  // True if async animation of the transform is allowed.
-  bool mAllowAsyncAnimation;
+  bool mIsTransformSeparator : 1;
   // True if this nsDisplayTransform should get flattened
-  bool mShouldFlatten;
+  bool mShouldFlatten : 1;
 };
 
 /* A display item that applies a perspective transformation to a single