Revert "Repaint when bgcolor animation is triggered"

This reverts commit bbf753e.

Reason for revert: Too much flakiness in blink_web_tests on Linux*

Recent failures:
- https://ci.chromium.org/p/chromium/builders/ci/Linux%20Tests/98274
- https://ci.chromium.org/p/chromium/builders/ci/linux-bfcache-rel/15065
- https://ci.chromium.org/p/chromium/builders/ci/linux-trusty-rel/21522

Original change's description:
> Repaint when bgcolor animation is triggered
>
> Right now when a bgcolor animation/transition is triggered, such
> as hovering over an element, we do not request a repaint of the
> element and thus we cannot composite the bgcolor animation.
>
> This CL fixes the problem by triggering a full repaint.
>
> Bug: 1177320
> Change-Id: I87dff5c11d109fc97f41c9b49e13b81613004281
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2698847
> Reviewed-by: Philip Rogers <pdr@chromium.org>
> Reviewed-by: Robert Flack <flackr@chromium.org>
> Commit-Queue: Xida Chen <xidachen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#857877}

Bug: 1177320
Change-Id: Ifabf8f703af522a6ea25aeac3e76926478a01610
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2719692
Reviewed-by: Jiewei Qian  <qjw@chromium.org>
Auto-Submit: Jiewei Qian  <qjw@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#857947}

third_party/blink/renderer/core/layout/layout_object.cc

@@ -2455,10 +2455,6 @@ void LayoutObject::SetStyle(scoped_refptr<const ComputedStyle> style,
        diff.CompositingReasonsChanged())) {
     SetNeedsPaintPropertyUpdate();
   }
-
-  if (!IsText() && diff.CompositablePaintEffectChanged()) {
-    SetShouldDoFullPaintInvalidationWithoutGeometryChange();
-  }
 }
 
 void LayoutObject::UpdateImageObservers(const ComputedStyle* old_style,

third_party/blink/renderer/core/style/computed_style.cc

@@ -959,11 +959,6 @@ void ComputedStyle::UpdatePropertySpecificDifferences(
       PotentialCompositingReasonsFor3DTransformChanged(other)) {
     diff.SetCompositingReasonsChanged();
   }
-
-  if (HasCurrentBackgroundColorAnimation() !=
-      other.HasCurrentBackgroundColorAnimation()) {
-    diff.SetCompositablePaintEffectChanged();
-  }
 }
 
 void ComputedStyle::AddPaintImage(StyleImage* image) {

third_party/blink/renderer/core/style/style_difference.h

@@ -43,8 +43,7 @@ class StyleDifference {
         visual_rect_update_(false),
         property_specific_differences_(0),
         scroll_anchor_disabling_property_changed_(false),
-        compositing_reasons_changed_(false),
-        compositable_paint_effect_changed_(false) {}
+        compositing_reasons_changed_(false) {}
 
   void Merge(StyleDifference other) {
     needs_paint_invalidation_ |= other.needs_paint_invalidation_;
@@ -56,15 +55,13 @@ class StyleDifference {
     scroll_anchor_disabling_property_changed_ |=
         other.scroll_anchor_disabling_property_changed_;
     compositing_reasons_changed_ |= other.compositing_reasons_changed_;
-    compositable_paint_effect_changed_ |=
-        other.compositable_paint_effect_changed_;
   }
 
   bool HasDifference() const {
     return needs_paint_invalidation_ || layout_type_ || needs_reshape_ ||
            property_specific_differences_ || recompute_visual_overflow_ ||
            visual_rect_update_ || scroll_anchor_disabling_property_changed_ ||
-           compositing_reasons_changed_ || compositable_paint_effect_changed_;
+           compositing_reasons_changed_;
   }
 
   bool HasAtMostPropertySpecificDifferences(
@@ -170,12 +167,6 @@ class StyleDifference {
     return compositing_reasons_changed_;
   }
   void SetCompositingReasonsChanged() { compositing_reasons_changed_ = true; }
-  bool CompositablePaintEffectChanged() const {
-    return compositable_paint_effect_changed_;
-  }
-  void SetCompositablePaintEffectChanged() {
-    compositable_paint_effect_changed_ = true;
-  }
 
  private:
   static constexpr int kPropertyDifferenceCount = 9;
@@ -193,9 +184,6 @@ class StyleDifference {
   unsigned property_specific_differences_ : kPropertyDifferenceCount;
   unsigned scroll_anchor_disabling_property_changed_ : 1;
   unsigned compositing_reasons_changed_ : 1;
-  // Designed for the effects such as background-color, whose animation can be
-  // composited using paint worklet infra.
-  unsigned compositable_paint_effect_changed_ : 1;
 };
 
 CORE_EXPORT std::ostream& operator<<(std::ostream&, const StyleDifference&);