[rm-for-spv175] Cleanup DisplayItem and PaintController about paired display items

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I3524d99338e48de260f1ff7acf7fa2cda537ed10
Reviewed-on: https://chromium-review.googlesource.com/1112313
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569897}

third_party/blink/renderer/core/paint/paint_info.h

@@ -115,7 +115,7 @@ struct CORE_EXPORT PaintInfo {
   }
 
   DisplayItem::Type DisplayItemTypeForClipping() const {
-    return DisplayItem::PaintPhaseToClipBoxType(phase);
+    return DisplayItem::PaintPhaseToClipType(phase);
   }
 
   const LayoutBoxModelObject* PaintContainer() const {

third_party/blink/renderer/core/paint/paint_layer_painter.cc

@@ -985,7 +985,7 @@ void PaintLayerPainter::PaintOverflowControlsForFragments(
           fragment_paint_chunk_properties.emplace(
               context.GetPaintController(),
               fragment.fragment_data->LocalBorderBoxProperties(), paint_layer_,
-              DisplayItem::kScrollOverflowControls);
+              DisplayItem::kOverflowControls);
         }
 
         // We need to apply the same clips and transforms that

third_party/blink/renderer/core/paint/scrollable_area_painter.cc

@@ -183,9 +183,9 @@ void ScrollableAreaPainter::PaintOverflowControls(
   DCHECK(properties);
   if (properties) {
     if (const auto* clip = properties->OverflowControlsClip()) {
-      scoped_paint_chunk_properties.emplace(
-          context.GetPaintController(), clip, box,
-          DisplayItem::kClipLayerOverflowControls);
+      scoped_paint_chunk_properties.emplace(context.GetPaintController(), clip,
+                                            box,
+                                            DisplayItem::kOverflowControls);
     }
   }
 

third_party/blink/renderer/platform/graphics/graphics_layer.cc

@@ -373,8 +373,7 @@ bool GraphicsLayer::Paint(const IntRect* interest_rect,
     if (auto record = tracking.UnderInvalidationRecord()) {
       // Add the under-invalidation overlay onto the painted result.
       GetPaintController().AppendDebugDrawingAfterCommit(
-          *this, std::move(record),
-          layer_state_ ? &layer_state_->state : nullptr);
+          *this, std::move(record), layer_state_->state);
       // Ensure the compositor will raster the under-invalidation overlay.
       layer_->SetNeedsDisplay();
     }

third_party/blink/renderer/platform/graphics/paint/display_item.cc

@@ -81,6 +81,7 @@ static WTF::String SpecialDrawingTypeAsDebugString(DisplayItem::Type type) {
     DEBUG_STRING_CASE(SVGImage);
     DEBUG_STRING_CASE(LinkHighlight);
     DEBUG_STRING_CASE(ImageAreaFocusRing);
+    DEBUG_STRING_CASE(OverflowControls);
     DEBUG_STRING_CASE(PageOverlay);
     DEBUG_STRING_CASE(PopupContainerBorder);
     DEBUG_STRING_CASE(PopupListBoxBackground);
@@ -131,50 +132,6 @@ static String ForeignLayerTypeAsDebugString(DisplayItem::Type type) {
   }
 }
 
-static String ScrollHitTestTypeAsDebugString(DisplayItem::Type type) {
-  switch (type) {
-    DEBUG_STRING_CASE(ScrollHitTest);
-    DEFAULT_CASE;
-  }
-}
-
-static WTF::String ClipTypeAsDebugString(DisplayItem::Type type) {
-  PAINT_PHASE_BASED_DEBUG_STRINGS(ClipBox);
-  PAINT_PHASE_BASED_DEBUG_STRINGS(ClipColumnBounds);
-  PAINT_PHASE_BASED_DEBUG_STRINGS(ClipLayerFragment);
-
-  switch (type) {
-    DEBUG_STRING_CASE(ClipFileUploadControlRect);
-    DEBUG_STRING_CASE(ClipFrameToVisibleContentRect);
-    DEBUG_STRING_CASE(ClipFrameScrollbars);
-    DEBUG_STRING_CASE(ClipLayerBackground);
-    DEBUG_STRING_CASE(ClipLayerColumnBounds);
-    DEBUG_STRING_CASE(ClipLayerFilter);
-    DEBUG_STRING_CASE(ClipLayerForeground);
-    DEBUG_STRING_CASE(ClipLayerParent);
-    DEBUG_STRING_CASE(ClipLayerOverflowControls);
-    DEBUG_STRING_CASE(ClipPopupListBoxFrame);
-    DEBUG_STRING_CASE(ClipScrollbarsToBoxBounds);
-    DEBUG_STRING_CASE(ClipSelectionImage);
-    DEFAULT_CASE;
-  }
-}
-
-static String ScrollTypeAsDebugString(DisplayItem::Type type) {
-  PAINT_PHASE_BASED_DEBUG_STRINGS(Scroll);
-  switch (type) {
-    DEBUG_STRING_CASE(ScrollOverflowControls);
-    DEFAULT_CASE;
-  }
-}
-
-static String Transform3DTypeAsDebugString(DisplayItem::Type type) {
-  switch (type) {
-    DEBUG_STRING_CASE(Transform3DElementTransform);
-    DEFAULT_CASE;
-  }
-}
-
 WTF::String DisplayItem::TypeAsDebugString(Type type) {
   if (IsDrawingType(type))
     return DrawingTypeAsDebugString(type);
@@ -182,43 +139,13 @@ WTF::String DisplayItem::TypeAsDebugString(Type type) {
   if (IsForeignLayerType(type))
     return ForeignLayerTypeAsDebugString(type);
 
-  if (IsClipType(type))
-    return ClipTypeAsDebugString(type);
-  if (IsEndClipType(type))
-    return "End" + ClipTypeAsDebugString(endClipTypeToClipType(type));
-
-  PAINT_PHASE_BASED_DEBUG_STRINGS(FloatClip);
-  if (type == kFloatClipClipPathBounds)
-    return "FloatClipClipPathBounds";
-  if (IsEndFloatClipType(type))
-    return "End" + TypeAsDebugString(endFloatClipTypeToFloatClipType(type));
-
-  if (IsScrollType(type))
-    return ScrollTypeAsDebugString(type);
-  if (IsEndScrollType(type))
-    return "End" + ScrollTypeAsDebugString(endScrollTypeToScrollType(type));
-
+  PAINT_PHASE_BASED_DEBUG_STRINGS(Clip);
+  PAINT_PHASE_BASED_DEBUG_STRINGS(Scroll);
   PAINT_PHASE_BASED_DEBUG_STRINGS(SVGTransform);
   PAINT_PHASE_BASED_DEBUG_STRINGS(SVGEffect);
 
-  if (IsTransform3DType(type))
-    return Transform3DTypeAsDebugString(type);
-  if (IsEndTransform3DType(type))
-    return "End" + Transform3DTypeAsDebugString(
-                       endTransform3DTypeToTransform3DType(type));
-
-  if (IsScrollHitTestType(type))
-    return ScrollHitTestTypeAsDebugString(type);
-
   switch (type) {
-    DEBUG_STRING_CASE(BeginFilter);
-    DEBUG_STRING_CASE(EndFilter);
-    DEBUG_STRING_CASE(BeginCompositing);
-    DEBUG_STRING_CASE(EndCompositing);
-    DEBUG_STRING_CASE(BeginTransform);
-    DEBUG_STRING_CASE(EndTransform);
-    DEBUG_STRING_CASE(BeginClipPath);
-    DEBUG_STRING_CASE(EndClipPath);
+    DEBUG_STRING_CASE(ScrollHitTest);
     DEBUG_STRING_CASE(LayerChunkBackground);
     DEBUG_STRING_CASE(LayerChunkNegativeZOrderChildren);
     DEBUG_STRING_CASE(LayerChunkDescendantBackgrounds);

third_party/blink/renderer/platform/graphics/paint/display_item.h

@@ -84,6 +84,7 @@ class PLATFORM_EXPORT DisplayItem {
     kSVGImage,
     kLinkHighlight,
     kImageAreaFocusRing,
+    kOverflowControls,
     kPageOverlay,
     kPopupContainerBorder,
     kPopupListBoxBackground,
@@ -127,47 +128,11 @@ class PLATFORM_EXPORT DisplayItem {
     kForeignLayerContentsWrapper,
     kForeignLayerLast = kForeignLayerContentsWrapper,
 
-    kClipFirst,
-    kClipBoxPaintPhaseFirst = kClipFirst,
-    kClipBoxPaintPhaseLast = kClipBoxPaintPhaseFirst + kPaintPhaseMax,
-    kClipColumnBoundsPaintPhaseFirst,
-    kClipColumnBoundsPaintPhaseLast =
-        kClipColumnBoundsPaintPhaseFirst + kPaintPhaseMax,
-    kClipLayerFragmentPaintPhaseFirst,
-    kClipLayerFragmentPaintPhaseLast =
-        kClipLayerFragmentPaintPhaseFirst + kPaintPhaseMax,
-    kClipFileUploadControlRect,
-    kClipFrameToVisibleContentRect,
-    kClipFrameScrollbars,
-    kClipLayerBackground,
-    kClipLayerColumnBounds,
-    kClipLayerFilter,
-    kClipLayerForeground,
-    kClipLayerParent,
-    kClipLayerOverflowControls,
-    kClipPopupListBoxFrame,
-    kClipScrollbarsToBoxBounds,
-    kClipSelectionImage,
-    kClipLast = kClipSelectionImage,
-
-    kEndClipFirst,
-    kEndClipLast = kEndClipFirst + kClipLast - kClipFirst,
-
-    kFloatClipFirst,
-    kFloatClipPaintPhaseFirst = kFloatClipFirst,
-    kFloatClipPaintPhaseLast = kFloatClipFirst + kPaintPhaseMax,
-    kFloatClipClipPathBounds,
-    kFloatClipLast = kFloatClipClipPathBounds,
-    kEndFloatClipFirst,
-    kEndFloatClipLast = kEndFloatClipFirst + kFloatClipLast - kFloatClipFirst,
-
-    kScrollFirst,
-    kScrollPaintPhaseFirst = kScrollFirst,
+    kClipPaintPhaseFirst,
+    kClipPaintPhaseLast = kClipPaintPhaseFirst + kPaintPhaseMax,
+
+    kScrollPaintPhaseFirst,
     kScrollPaintPhaseLast = kScrollPaintPhaseFirst + kPaintPhaseMax,
-    kScrollOverflowControls,
-    kScrollLast = kScrollOverflowControls,
-    kEndScrollFirst,
-    kEndScrollLast = kEndScrollFirst + kScrollLast - kScrollFirst,
 
     kSVGTransformPaintPhaseFirst,
     kSVGTransformPaintPhaseLast = kSVGTransformPaintPhaseFirst + kPaintPhaseMax,
@@ -175,21 +140,6 @@ class PLATFORM_EXPORT DisplayItem {
     kSVGEffectPaintPhaseFirst,
     kSVGEffectPaintPhaseLast = kSVGEffectPaintPhaseFirst + kPaintPhaseMax,
 
-    kTransform3DFirst,
-    kTransform3DElementTransform = kTransform3DFirst,
-    kTransform3DLast = kTransform3DElementTransform,
-    kEndTransform3DFirst,
-    kEndTransform3DLast =
-        kEndTransform3DFirst + kTransform3DLast - kTransform3DFirst,
-
-    kBeginFilter,
-    kEndFilter,
-    kBeginCompositing,
-    kEndCompositing,
-    kBeginTransform,
-    kEndTransform,
-    kBeginClipPath,
-    kEndClipPath,
     kScrollHitTest,
 
     kLayerChunkBackground,
@@ -308,11 +258,6 @@ class PLATFORM_EXPORT DisplayItem {
                              k##Category1##First);                            \
   }
 
-#define DEFINE_PAIRED_CATEGORY_METHODS(Category, category) \
-  DEFINE_CATEGORY_METHODS(Category)                        \
-  DEFINE_CATEGORY_METHODS(End##Category)                   \
-  DEFINE_CONVERSION_METHODS(Category, category, End##Category, end##Category)
-
 #define DEFINE_PAINT_PHASE_CONVERSION_METHOD(Category)                \
   static Type PaintPhaseTo##Category##Type(PaintPhase paint_phase) {  \
     static_assert(                                                    \
@@ -329,22 +274,11 @@ class PLATFORM_EXPORT DisplayItem {
 
   DEFINE_CATEGORY_METHODS(ForeignLayer)
 
-  DEFINE_PAIRED_CATEGORY_METHODS(Clip, clip)
-  DEFINE_PAINT_PHASE_CONVERSION_METHOD(ClipLayerFragment)
-  DEFINE_PAINT_PHASE_CONVERSION_METHOD(ClipBox)
-  DEFINE_PAINT_PHASE_CONVERSION_METHOD(ClipColumnBounds)
-
-  DEFINE_PAIRED_CATEGORY_METHODS(FloatClip, floatClip)
-  DEFINE_PAINT_PHASE_CONVERSION_METHOD(FloatClip)
-
-  DEFINE_PAIRED_CATEGORY_METHODS(Scroll, scroll)
+  DEFINE_PAINT_PHASE_CONVERSION_METHOD(Clip)
   DEFINE_PAINT_PHASE_CONVERSION_METHOD(Scroll)
-
   DEFINE_PAINT_PHASE_CONVERSION_METHOD(SVGTransform)
   DEFINE_PAINT_PHASE_CONVERSION_METHOD(SVGEffect)
 
-  DEFINE_PAIRED_CATEGORY_METHODS(Transform3D, transform3D)
-
   static bool IsScrollHitTestType(Type type) { return type == kScrollHitTest; }
   bool IsScrollHitTest() const { return IsScrollHitTestType(GetType()); }
 
@@ -354,15 +288,6 @@ class PLATFORM_EXPORT DisplayItem {
     return !SkippedCache() && IsCacheableType(GetType());
   }
 
-  virtual bool IsBegin() const { return false; }
-  virtual bool IsEnd() const { return false; }
-
-#if DCHECK_IS_ON()
-  virtual bool IsEndAndPairedWith(DisplayItem::Type other_type) const {
-    return false;
-  }
-#endif
-
   virtual bool Equals(const DisplayItem& other) const {
     // Failure of this DCHECK would cause bad casts in subclasses.
     SECURITY_CHECK(!is_tombstone_);
@@ -418,36 +343,6 @@ inline bool operator!=(const DisplayItem::Id& a, const DisplayItem::Id& b) {
   return !(a == b);
 }
 
-class PLATFORM_EXPORT PairedBeginDisplayItem : public DisplayItem {
- protected:
-  PairedBeginDisplayItem(const DisplayItemClient& client,
-                         Type type,
-                         size_t derived_size)
-      : DisplayItem(client, type, derived_size) {
-    DCHECK(!RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
-  }
-
- private:
-  bool IsBegin() const final { return true; }
-};
-
-class PLATFORM_EXPORT PairedEndDisplayItem : public DisplayItem {
- protected:
-  PairedEndDisplayItem(const DisplayItemClient& client,
-                       Type type,
-                       size_t derived_size)
-      : DisplayItem(client, type, derived_size) {
-    DCHECK(!RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
-  }
-
-#if DCHECK_IS_ON()
-  bool IsEndAndPairedWith(DisplayItem::Type other_type) const override = 0;
-#endif
-
- private:
-  bool IsEnd() const final { return true; }
-};
-
 }  // namespace blink
 
 #endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_PAINT_DISPLAY_ITEM_H_

third_party/blink/renderer/platform/graphics/paint/display_item_list.h

@@ -56,19 +56,6 @@ class PLATFORM_EXPORT DisplayItemList
     return result;
   }
 
-  // This is used by PaintUnderInvalidationChecking in SPv1 to restore a
-  // paired-begin display item that was moved to the new display item list then
-  // was removed because the pair is a no-op. This ensures that we won't compare
-  // the next new display item against the tombstone display item.
-  void RestoreTombstone(size_t index, DisplayItem& item) {
-    DCHECK(!RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
-    DCHECK((*this)[index].IsTombstone());
-    SECURITY_CHECK((*this)[index].DerivedSize() == item.DerivedSize());
-    memcpy(static_cast<void*>(&(*this)[index]), static_cast<void*>(&item),
-           item.DerivedSize());
-    new (&item) DisplayItem;
-  }
-
   // Useful for iterating with a range-based for loop.
   template <typename Iterator>
   class Range {

third_party/blink/renderer/platform/graphics/paint/paint_controller.cc

@@ -212,56 +212,11 @@ void PaintController::EndSubsequence(const DisplayItemClient& client,
   last_cached_subsequence_end_ = end;
 }
 
-bool PaintController::LastDisplayItemIsNoopBegin() const {
-  DCHECK(!RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
-
-  if (new_display_item_list_.IsEmpty())
-    return false;
-
-  const auto& last_display_item = new_display_item_list_.Last();
-  return last_display_item.IsBegin() && !last_display_item.DrawsContent();
-}
-
 bool PaintController::LastDisplayItemIsSubsequenceEnd() const {
   return !new_cached_subsequences_.IsEmpty() &&
          last_cached_subsequence_end_ == new_display_item_list_.size();
 }
 
-void PaintController::RemoveLastDisplayItem() {
-  DCHECK(!RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
-
-  if (new_display_item_list_.IsEmpty())
-    return;
-
-#if DCHECK_IS_ON()
-  // Also remove the index pointing to the removed display item.
-  IndicesByClientMap::iterator it = new_display_item_indices_by_client_.find(
-      &new_display_item_list_.Last().Client());
-  if (it != new_display_item_indices_by_client_.end()) {
-    Vector<size_t>& indices = it->value;
-    if (!indices.IsEmpty() &&
-        indices.back() == (new_display_item_list_.size() - 1))
-      indices.pop_back();
-  }
-#endif
-
-  if (RuntimeEnabledFeatures::PaintUnderInvalidationCheckingEnabled() &&
-      IsCheckingUnderInvalidation()) {
-    if (skipped_probable_under_invalidation_count_) {
-      --skipped_probable_under_invalidation_count_;
-    } else {
-      DCHECK(under_invalidation_checking_begin_);
-      --under_invalidation_checking_begin_;
-      // The old display item is a tombstone because it was matched by the begin
-      // display item being removed. Restore the tombstone so that we can match
-      // the next new display item against it.
-      current_paint_artifact_.GetDisplayItemList().RestoreTombstone(
-          under_invalidation_checking_begin_, new_display_item_list_.Last());
-    }
-  }
-  new_display_item_list_.RemoveLast();
-}
-
 const DisplayItem* PaintController::LastDisplayItem(unsigned offset) {
   if (offset < new_display_item_list_.size())
     return &new_display_item_list_[new_display_item_list_.size() - offset - 1];
@@ -279,10 +234,8 @@ void PaintController::ProcessNewItem(DisplayItem& display_item) {
         &display_item.Client(), display_item.Client().DebugName());
   }
 
-  if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled()) {
   size_t last_chunk_index = new_paint_chunks_.LastChunkIndex();
-    bool chunk_added =
-        new_paint_chunks_.IncrementDisplayItemIndex(display_item);
+  bool chunk_added = new_paint_chunks_.IncrementDisplayItemIndex(display_item);
   auto& last_chunk = new_paint_chunks_.LastChunk();
 
 #if DCHECK_IS_ON()
@@ -302,17 +255,8 @@ void PaintController::ProcessNewItem(DisplayItem& display_item) {
   last_chunk.outset_for_raster_effects =
       std::max(last_chunk.outset_for_raster_effects,
                display_item.OutsetForRasterEffects());
-  }
 
 #if DCHECK_IS_ON()
-  // Verify noop begin/end pairs have been removed.
-  if (new_display_item_list_.size() >= 2 && display_item.IsEnd()) {
-    const auto& begin_display_item =
-        new_display_item_list_[new_display_item_list_.size() - 2];
-    if (begin_display_item.IsBegin() && !begin_display_item.DrawsContent())
-      DCHECK(!display_item.IsEndAndPairedWith(begin_display_item.GetType()));
-  }
-
   if (display_item.IsCacheable()) {
     size_t index = FindMatchingItemFromIndex(
         display_item.GetId(), new_display_item_indices_by_client_,
@@ -507,21 +451,13 @@ void PaintController::CopyCachedSubsequence(size_t begin_index,
   DisplayItem* cached_item =
       &current_paint_artifact_.GetDisplayItemList()[begin_index];
 
-  Vector<PaintChunk>::const_iterator cached_chunk;
-  base::Optional<PropertyTreeState> properties_before_subsequence;
-  if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled()) {
-    cached_chunk =
+  auto* cached_chunk =
       current_paint_artifact_.FindChunkByDisplayItemIndex(begin_index);
   DCHECK(cached_chunk != current_paint_artifact_.PaintChunks().end());
-
-    properties_before_subsequence =
+  auto properties_before_subsequence =
       new_paint_chunks_.CurrentPaintChunkProperties();
   UpdateCurrentPaintChunkPropertiesUsingIdWithFragment(
       cached_chunk->id, cached_chunk->properties.GetPropertyTreeState());
-  } else {
-    // Avoid uninitialized variable error on Windows.
-    cached_chunk = current_paint_artifact_.PaintChunks().begin();
-  }
 
   for (size_t current_index = begin_index; current_index < end_index;
        ++current_index) {
@@ -531,8 +467,7 @@ void PaintController::CopyCachedSubsequence(size_t begin_index,
     DCHECK(cached_item->Client().IsAlive());
 #endif
 
-    if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled() &&
-        current_index == cached_chunk->end_index) {
+    if (current_index == cached_chunk->end_index) {
       ++cached_chunk;
       DCHECK(cached_chunk != current_paint_artifact_.PaintChunks().end());
       new_paint_chunks_.ForceNewChunk();
@@ -554,22 +489,20 @@ void PaintController::CopyCachedSubsequence(size_t begin_index,
 #endif
 
     ProcessNewItem(MoveItemFromCurrentListToNewList(current_index));
-    if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled()) {
     DCHECK((!new_paint_chunks_.LastChunk().is_cacheable &&
             !cached_chunk->is_cacheable) ||
            new_paint_chunks_.LastChunk().Matches(*cached_chunk));
   }
-  }
 
   if (RuntimeEnabledFeatures::PaintUnderInvalidationCheckingEnabled()) {
     under_invalidation_checking_end_ = end_index;
     DCHECK(IsCheckingUnderInvalidation());
-  } else if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled()) {
+  } else {
     // Restore properties and force new chunk for any trailing display items
     // after the cached subsequence without new properties.
     new_paint_chunks_.ForceNewChunk();
     UpdateCurrentPaintChunkProperties(base::nullopt,
-                                      *properties_before_subsequence);
+                                      properties_before_subsequence);
   }
 }
 
@@ -579,7 +512,6 @@ void PaintController::ResetCurrentListIndices() {
   next_chunk_to_match_ = 0;
   under_invalidation_checking_begin_ = 0;
   under_invalidation_checking_end_ = 0;
-  skipped_probable_under_invalidation_count_ = 0;
 }
 
 DISABLE_CFI_PERF
@@ -596,8 +528,7 @@ void PaintController::CommitNewDisplayItems() {
   new_paint_chunk_indices_by_client_.clear();
 #endif
 
-  if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled() &&
-      !new_display_item_list_.IsEmpty())
+  if (!new_display_item_list_.IsEmpty())
     GenerateRasterInvalidations(new_paint_chunks_.LastChunk());
 
   auto old_cache_generation = current_cache_generation_;
@@ -613,7 +544,6 @@ void PaintController::CommitNewDisplayItems() {
   Vector<const DisplayItemClient*> skipped_cache_clients;
   for (const auto& item : new_display_item_list_) {
     const auto& client = item.Client();
-    if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled())
     client.ClearPartialInvalidationVisualRect();
 
     if (item.IsCacheable()) {
@@ -648,12 +578,10 @@ void PaintController::CommitNewDisplayItems() {
   out_of_order_chunk_indices_.clear();
   items_moved_into_new_list_.clear();
 
-  if (RuntimeEnabledFeatures::SlimmingPaintV175Enabled()) {
   for (const auto& chunk : current_paint_artifact_.PaintChunks()) {
     if (chunk.id.client.IsJustCreated())
       chunk.id.client.ClearIsJustCreated();
   }
-  }
 
   // We'll allocate the initial buffer when we start the next paint.
   new_display_item_list_ = DisplayItemList(0);
@@ -724,7 +652,7 @@ size_t PaintController::ApproximateUnsharedMemoryUsage() const {
 void PaintController::AppendDebugDrawingAfterCommit(
     const DisplayItemClient& display_item_client,
     sk_sp<const PaintRecord> record,
-    const PropertyTreeState* property_tree_state) {
+    const PropertyTreeState& property_tree_state) {
   DCHECK(!RuntimeEnabledFeatures::SlimmingPaintV2Enabled());
   DCHECK(new_display_item_list_.IsEmpty());
   auto& display_item_list = current_paint_artifact_.GetDisplayItemList();
@@ -733,17 +661,13 @@ void PaintController::AppendDebugDrawingAfterCommit(
           display_item_client, DisplayItem::kDebugDrawing, std::move(record));
   display_item.SetSkippedCache();
 
-  if (property_tree_state) {
-    DCHECK(RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
   // Create a PaintChunk for the debug drawing.
   current_paint_artifact_.PaintChunks().emplace_back(
       display_item_list.size() - 1, display_item_list.size(),
-        display_item.GetId(), *property_tree_state);
-  }
+      display_item.GetId(), property_tree_state);
 }
 
 void PaintController::GenerateRasterInvalidations(PaintChunk& new_chunk) {
-  DCHECK(RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
   if (new_chunk.begin_index >=
       current_cached_subsequence_begin_index_in_new_list_)
     return;
@@ -821,8 +745,6 @@ void PaintController::TrackRasterInvalidation(const DisplayItemClient& client,
 void PaintController::GenerateRasterInvalidationsComparingChunks(
     PaintChunk& new_chunk,
     const PaintChunk& old_chunk) {
-  DCHECK(RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
-
   // TODO(wangxianzhu): Optimize paint offset change.
 
   struct OldAndNewDisplayItems {
@@ -1086,41 +1008,18 @@ void PaintController::CheckUnderInvalidation() {
     return;
   }
 
-  size_t old_item_index = under_invalidation_checking_begin_ +
-                          skipped_probable_under_invalidation_count_;
+  size_t old_item_index = under_invalidation_checking_begin_;
   DisplayItem* old_item =
       old_item_index < current_paint_artifact_.GetDisplayItemList().size()
           ? &current_paint_artifact_.GetDisplayItemList()[old_item_index]
           : nullptr;
 
-  bool old_and_new_equal = (old_item && new_item.Equals(*old_item));
-  if (!old_and_new_equal) {
-    if (new_item.IsBegin()) {
-      // Temporarily skip mismatching begin display item which may be removed
-      // when we remove a no-op pair.
-      ++skipped_probable_under_invalidation_count_;
-      return;
-    }
-    if (new_item.IsDrawing() &&
-        skipped_probable_under_invalidation_count_ == 1) {
-      DCHECK_GE(new_display_item_list_.size(), 2u);
-      if (new_display_item_list_[new_display_item_list_.size() - 2].GetType() ==
-          DisplayItem::kBeginCompositing) {
-        // This might be a drawing item between a pair of begin/end compositing
-        // display items that will be folded into a single drawing display item.
-        ++skipped_probable_under_invalidation_count_;
-        return;
-      }
-    }
-  }
-
-  if (skipped_probable_under_invalidation_count_ || !old_and_new_equal) {
+  if (!old_item || !new_item.Equals(*old_item)) {
     // If we ever skipped reporting any under-invalidations, report the earliest
     // one.
     ShowUnderInvalidationError(
         "under-invalidation: display item changed",
-        new_display_item_list_[new_display_item_list_.size() -
-                               skipped_probable_under_invalidation_count_ - 1],
+        new_display_item_list_.Last(),
         &current_paint_artifact_
              .GetDisplayItemList()[under_invalidation_checking_begin_]);
     CHECK(false);

third_party/blink/renderer/platform/graphics/paint/paint_controller.h

@@ -123,23 +123,6 @@ class PLATFORM_EXPORT PaintController {
     ProcessNewItem(display_item);
   }
 
-  // Creates and appends an ending display item to pair with a preceding
-  // beginning item iff the display item actually draws content. For no-op
-  // items, rather than creating an ending item, the begin item will
-  // instead be removed, thereby maintaining brevity of the list. If display
-  // item construction is disabled, no list mutations will be performed.
-  template <typename DisplayItemClass, typename... Args>
-  void EndItem(Args&&... args) {
-    DCHECK(!RuntimeEnabledFeatures::SlimmingPaintV175Enabled());
-
-    if (DisplayItemConstructionIsDisabled())
-      return;
-    if (LastDisplayItemIsNoopBegin())
-      RemoveLastDisplayItem();
-    else
-      CreateAndAppend<DisplayItemClass>(std::forward<Args>(args)...);
-  }
-
   // Tries to find the cached drawing display item corresponding to the given
   // parameters. If found, appends the cached display item to the new display
   // list and returns true. Otherwise returns false.
@@ -155,8 +138,6 @@ class PLATFORM_EXPORT PaintController {
   // BeginSubsequence().
   void EndSubsequence(const DisplayItemClient&, size_t start);
 
-  // True if the last display item is a begin that doesn't draw content.
-  void RemoveLastDisplayItem();
   const DisplayItem* LastDisplayItem(unsigned offset);
 
   void BeginSkippingCache() { ++skipping_cache_count_; }
@@ -212,7 +193,7 @@ class PLATFORM_EXPORT PaintController {
 
   void AppendDebugDrawingAfterCommit(const DisplayItemClient&,
                                      sk_sp<const PaintRecord>,
-                                     const PropertyTreeState*);
+                                     const PropertyTreeState&);
 
 #if DCHECK_IS_ON()
   void ShowDebugData() const;
@@ -277,8 +258,6 @@ class PLATFORM_EXPORT PaintController {
   void InvalidateAllForTesting() { InvalidateAllInternal(); }
   void InvalidateAllInternal();
 
-  bool LastDisplayItemIsNoopBegin() const;
-
   void EnsureNewDisplayItemListInitialCapacity() {
     if (new_display_item_list_.IsEmpty()) {
       // TODO(wangxianzhu): Consider revisiting this heuristic.
@@ -458,10 +437,6 @@ class PLATFORM_EXPORT PaintController {
   size_t under_invalidation_checking_begin_;
   size_t under_invalidation_checking_end_;
 
-  // Number of probable under-invalidations that have been skipped temporarily
-  // because the mismatching display items may be removed in the future because
-  // of no-op pairs or compositing folding.
-  int skipped_probable_under_invalidation_count_;
   String under_invalidation_message_prefix_;
 
   struct RasterInvalidationTrackingInfo {

third_party/blink/renderer/platform/graphics/paint/paint_controller_test.h

@@ -130,7 +130,7 @@ const DisplayItem::Type kForegroundType =
 const DisplayItem::Type kDocumentBackgroundType =
     DisplayItem::kDocumentBackground;
 const DisplayItem::Type kScrollHitTestType = DisplayItem::kScrollHitTest;
-const DisplayItem::Type kClipType = DisplayItem::kClipFirst;
+const DisplayItem::Type kClipType = DisplayItem::kClipPaintPhaseFirst;
 
 }  // namespace blink