[CompositeAfterPaint] Disable some compositing input update code in P…

…aintLayer

This marks code for future removal, and avoids crash on unexpected
compositing input update flag.

Change-Id: I16086f5a2e3541a4d4930a9f8282ed2b3e2c8b66
Reviewed-on: https://chromium-review.googlesource.com/c/1383044
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617907}

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

@@ -148,8 +148,10 @@ PaintLayer::PaintLayer(LayoutBoxModelObject& layout_object)
 #endif
       has3d_transformed_descendant_(false),
       contains_dirty_overlay_scrollbars_(false),
-      needs_ancestor_dependent_compositing_inputs_update_(true),
-      child_needs_compositing_inputs_update_(true),
+      needs_ancestor_dependent_compositing_inputs_update_(
+          !RuntimeEnabledFeatures::CompositeAfterPaintEnabled()),
+      child_needs_compositing_inputs_update_(
+          !RuntimeEnabledFeatures::CompositeAfterPaintEnabled()),
       has_compositing_descendant_(false),
       should_isolate_composited_descendants_(false),
       lost_grouped_mapping_(false),
@@ -167,7 +169,8 @@ PaintLayer::PaintLayer(LayoutBoxModelObject& layout_object)
       filter_on_effect_node_dirty_(false),
       is_under_svg_hidden_container_(false),
       descendant_has_direct_or_scrolling_compositing_reason_(false),
-      needs_compositing_reasons_update_(true),
+      needs_compositing_reasons_update_(
+          !RuntimeEnabledFeatures::CompositeAfterPaintEnabled()),
       descendant_may_need_compositing_requirements_update_(false),
       needs_compositing_layer_assignment_(false),
       descendant_needs_compositing_layer_assignment_(false),
@@ -1054,12 +1057,15 @@ void PaintLayer::SetNeedsCompositingInputsUpdate() {
 
   // TODO(chrishtr): These are a bit of a heavy hammer, because not all
   // things which require compositing inputs update require a descendant-
-  // dependent flags udpate. Reduce call sites after CAP launch allows
+  // dependent flags update. Reduce call sites after CAP launch allows
   /// removal of CompositingInputsUpdater.
   MarkAncestorChainForDescendantDependentFlagsUpdate();
 }
 
 void PaintLayer::SetNeedsCompositingInputsUpdateInternal() {
+  if (RuntimeEnabledFeatures::CompositeAfterPaintEnabled())
+    return;
+
   needs_ancestor_dependent_compositing_inputs_update_ = true;
 
   for (PaintLayer* current = this;
@@ -1075,11 +1081,13 @@ void PaintLayer::SetNeedsCompositingInputsUpdateInternal() {
 
 void PaintLayer::UpdateAncestorDependentCompositingInputs(
     const AncestorDependentCompositingInputs& compositing_inputs) {
+  DCHECK(!RuntimeEnabledFeatures::CompositeAfterPaintEnabled());
   EnsureAncestorDependentCompositingInputs() = compositing_inputs;
   needs_ancestor_dependent_compositing_inputs_update_ = false;
 }
 
 void PaintLayer::ClearChildNeedsCompositingInputsUpdate() {
+  DCHECK(!RuntimeEnabledFeatures::CompositeAfterPaintEnabled());
   DCHECK(!NeedsCompositingInputsUpdate());
   child_needs_compositing_inputs_update_ = false;
 }

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

@@ -1742,7 +1742,8 @@ TEST_P(PaintLayerTest, BackgroundIsKnownToBeOpaqueInRectChildren) {
       LayoutRect(0, 0, 100, 100), false));
 }
 
-TEST_P(PaintLayerTest, ChangeAlphaNeedsCompositingInputs) {
+TEST_P(PaintLayerTest,
+       ChangeAlphaNeedsCompositingInputsAndPaintPropertyUpdate) {
   SetBodyInnerHTML(R"HTML(
     <style>
       #target {
@@ -1756,10 +1757,20 @@ TEST_P(PaintLayerTest, ChangeAlphaNeedsCompositingInputs) {
     </div>
   )HTML");
   PaintLayer* target = GetPaintLayerByElementId("target");
+  EXPECT_FALSE(target->NeedsCompositingInputsUpdate());
+  EXPECT_FALSE(target->GetLayoutObject().NeedsPaintPropertyUpdate());
+  EXPECT_FALSE(target->Parent()->GetLayoutObject().NeedsPaintPropertyUpdate());
+
   StyleDifference diff;
   diff.SetHasAlphaChanged();
   target->StyleDidChange(diff, target->GetLayoutObject().Style());
-  EXPECT_TRUE(target->NeedsCompositingInputsUpdate());
+  if (RuntimeEnabledFeatures::CompositeAfterPaintEnabled())
+    EXPECT_FALSE(target->NeedsCompositingInputsUpdate());
+  else
+    EXPECT_TRUE(target->NeedsCompositingInputsUpdate());
+  EXPECT_TRUE(target->GetLayoutObject().NeedsPaintPropertyUpdate());
+  // See the TODO in PaintLayer::SetNeedsCompositingInputsUpdate().
+  EXPECT_TRUE(target->Parent()->GetLayoutObject().NeedsPaintPropertyUpdate());
 }
 
 }  // namespace blink

third_party/blink/web_tests/FlagExpectations/enable-blink-features=CompositeAfterPaint

@@ -126,13 +126,13 @@ Bug(none) compositing/overflow/scroll-parent-with-non-stacking-context-composite
 Bug(none) compositing/overflow/scrollbar-layer-placement.html [ Failure ]
 Bug(none) compositing/overflow/scrollbar-layer-placement-negative-z-index-child.html [ Failure ]
 Bug(none) compositing/overflow/scrolling-content-clip-to-viewport.html [ Failure ]
-crbug.com/667946 compositing/overflow/scrolls-with-respect-to-nested.html [ Failure Crash ]
-crbug.com/667946 compositing/overflow/scrolls-with-respect-to-transform.html [ Failure Crash ]
-crbug.com/667946 compositing/overflow/scrolls-with-respect-to.html [ Failure Crash ]
+crbug.com/667946 compositing/overflow/scrolls-with-respect-to-nested.html [ Failure ]
+crbug.com/667946 compositing/overflow/scrolls-with-respect-to-transform.html [ Failure ]
+crbug.com/667946 compositing/overflow/scrolls-with-respect-to.html [ Failure ]
 Bug(none) compositing/overflow/textarea-scroll-touch.html [ Failure ]
 Bug(none) compositing/overflow/universal-accelerated-overflow-scroll.html [ Failure ]
-Bug(none) compositing/reflections/deeply-nested-reflections.html [ Failure Crash ]
-Bug(none) compositing/reflections/nested-reflection-mask-change.html [ Failure Crash ]
+Bug(none) compositing/reflections/deeply-nested-reflections.html [ Failure ]
+Bug(none) compositing/reflections/nested-reflection-mask-change.html [ Failure ]
 Bug(none) compositing/rtl/rtl-absolute-overflow-scrolled.html [ Failure Crash ]
 Bug(none) compositing/rtl/rtl-absolute-overflow.html [ Failure Crash ]
 Bug(none) compositing/rtl/rtl-fixed-overflow-scrolled.html [ Failure Crash ]