[root layer scrolls] Invalidate scrolling contents on size changes

This patch factors ViewPaintInvalidator into BoxPaintInvalidator
which reuses BoxPaintInvalidator's logic for invalidating the
scrolling contents layer. This fixes one root layer scrolling test.

Bug: 781419

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_root_layer_scrolls;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I62a84be195920a63e2db1207d4e329450eebeabf
Reviewed-on: https://chromium-review.googlesource.com/759738
Commit-Queue: Philip Rogers <pdr@chromium.org>
Reviewed-by: Steve Kobes <skobes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515969}

third_party/WebKit/LayoutTests/FlagExpectations/root-layer-scrolls

@@ -96,7 +96,6 @@ crbug.com/417782 paint/invalidation/resize-iframe-text.html [ Failure ]
 crbug.com/417782 paint/invalidation/svg/absolute-sized-document-no-scrollbars.svg [ Failure ]
 crbug.com/417782 paint/invalidation/svg/deep-nested-embedded-svg-size-changes-no-layout-triggers-1.html [ Failure ]
 crbug.com/417782 paint/invalidation/svg/deep-nested-embedded-svg-size-changes-no-layout-triggers-2.html [ Failure ]
-crbug.com/417782 paint/invalidation/viewport-gradient-background-html-resize.html [ Crash ]
 crbug.com/417782 paint/invalidation/window-resize-background-image-fixed-centered-composited.html [ Failure ]
 crbug.com/417782 paint/invalidation/window-resize-background-image-fixed-centered.html [ Failure ]
 crbug.com/417782 paint/invalidation/window-resize-background-image-generated.html [ Failure ]

third_party/WebKit/LayoutTests/flag-specific/root-layer-scrolls/paint/invalidation/viewport-gradient-background-html-resize-expected.txt

+{
+  "layers": [
+    {
+      "name": "LayoutView #document",
+      "bounds": [800, 600],
+      "backgroundColor": "#FFFFFF"
+    },
+    {
+      "name": "Scrolling Layer",
+      "bounds": [800, 600],
+      "drawsContent": false
+    },
+    {
+      "name": "Scrolling Contents Layer",
+      "bounds": [800, 600],
+      "contentsOpaque": true,
+      "backgroundColor": "#FFFFFF",
+      "paintInvalidations": [
+        {
+          "object": "LayoutView #document",
+          "rect": [0, 0, 800, 600],
+          "reason": "background on scrolling contents layer"
+        },
+        {
+          "object": "LayoutBlockFlow BODY",
+          "rect": [0, 0, 800, 200],
+          "reason": "geometry"
+        }
+      ]
+    }
+  ],
+  "objectPaintInvalidations": [
+    {
+      "object": "Scrolling Contents Layer",
+      "reason": "background on scrolling contents layer"
+    },
+    {
+      "object": "LayoutBlockFlow BODY",
+      "reason": "geometry"
+    }
+  ]
+}
+

third_party/WebKit/Source/core/layout/LayoutView.cpp

@@ -41,7 +41,6 @@
 #include "core/page/ChromeClient.h"
 #include "core/page/Page.h"
 #include "core/paint/PaintLayer.h"
-#include "core/paint/ViewPaintInvalidator.h"
 #include "core/paint/ViewPainter.h"
 #include "core/paint/compositing/PaintLayerCompositor.h"
 #include "core/svg/SVGDocumentExtensions.h"
@@ -450,11 +449,6 @@ void LayoutView::ComputeSelfHitTestRects(Vector<LayoutRect>& rects,
                              LayoutSize(GetFrameView()->ContentsSize())));
 }
 
-PaintInvalidationReason LayoutView::InvalidatePaint(
-    const PaintInvalidatorContext& context) const {
-  return ViewPaintInvalidator(*this, context).InvalidatePaint();
-}
-
 void LayoutView::Paint(const PaintInfo& paint_info,
                        const LayoutPoint& paint_offset) const {
   ViewPainter(*this).Paint(paint_info, paint_offset);

third_party/WebKit/Source/core/layout/LayoutView.h

@@ -140,9 +140,6 @@ class CORE_EXPORT LayoutView final : public LayoutBlockFlow {
 
   void InvalidatePaintForViewAndCompositedLayers();
 
-  PaintInvalidationReason InvalidatePaint(
-      const PaintInvalidatorContext&) const override;
-
   void Paint(const PaintInfo&, const LayoutPoint&) const override;
   void PaintBoxDecorationBackground(const PaintInfo&,
                                     const LayoutPoint&) const override;

third_party/WebKit/Source/core/paint/BUILD.gn

@@ -218,8 +218,6 @@ blink_core_sources("paint") {
     "TransformRecorder.h",
     "VideoPainter.cpp",
     "VideoPainter.h",
-    "ViewPaintInvalidator.cpp",
-    "ViewPaintInvalidator.h",
     "ViewPainter.cpp",
     "ViewPainter.h",
     "compositing/CompositedLayerMapping.cpp",

third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp

@@ -159,7 +159,8 @@ PaintInvalidationReason BoxPaintInvalidator::ComputePaintInvalidationReason() {
   return PaintInvalidationReason::kIncremental;
 }
 
-bool BoxPaintInvalidator::BackgroundGeometryDependsOnLayoutOverflowRect() {
+bool BoxPaintInvalidator::BackgroundGeometryDependsOnLayoutOverflowRect()
+    const {
   return !box_.IsDocumentElement() && !box_.BackgroundStolenForBeingBody() &&
          box_.StyleRef()
              .BackgroundLayers()
@@ -200,11 +201,49 @@ bool BoxPaintInvalidator::ShouldFullyInvalidateBackgroundOnLayoutOverflowChange(
   return false;
 }
 
+bool BoxPaintInvalidator::ViewBackgroundShouldFullyInvalidate() const {
+  DCHECK(box_.IsLayoutView());
+  // Fixed attachment background is handled in LayoutView::layout().
+  // TODO(wangxianzhu): Combine code for fixed-attachment background when we
+  // enable rootLayerScrolling permanently.
+  if (box_.StyleRef().HasEntirelyFixedBackground())
+    return false;
+
+  // LayoutView's non-fixed-attachment background is positioned in the
+  // document element and needs to invalidate if the size changes.
+  // See: https://drafts.csswg.org/css-backgrounds-3/#root-background.
+  if (BackgroundGeometryDependsOnLayoutOverflowRect()) {
+    Element* document_element = box_.GetDocument().documentElement();
+    if (document_element) {
+      const auto* document_background = document_element->GetLayoutObject();
+      if (document_background && document_background->IsBox()) {
+        // TODO(pdr): Change this to use layout overflow instead of size because
+        // the background size actually depends on the layout overflow.
+        LayoutSize old_size = ToLayoutBox(document_background)->PreviousSize();
+        LayoutSize new_size = ToLayoutBox(document_background)->Size();
+        const auto& layers = box_.StyleRef().BackgroundLayers();
+        if (old_size.Width() != new_size.Width() &&
+            LayoutBox::MustInvalidateFillLayersPaintOnWidthChange(layers)) {
+          return true;
+        }
+        if (old_size.Height() != new_size.Height() &&
+            LayoutBox::MustInvalidateFillLayersPaintOnHeightChange(layers)) {
+          return true;
+        }
+      }
+    }
+  }
+  return false;
+}
+
 BoxPaintInvalidator::BackgroundInvalidationType
 BoxPaintInvalidator::ComputeBackgroundInvalidation() {
   if (box_.BackgroundChangedSinceLastPaintInvalidation())
     return BackgroundInvalidationType::kFull;
 
+  if (box_.IsLayoutView() && ViewBackgroundShouldFullyInvalidate())
+    return BackgroundInvalidationType::kFull;
+
   bool layout_overflow_change_causes_invalidation =
       (BackgroundGeometryDependsOnLayoutOverflowRect() ||
        BackgroundPaintsOntoScrollingContentsLayer());

third_party/WebKit/Source/core/paint/BoxPaintInvalidator.h

@@ -30,11 +30,12 @@ class CORE_EXPORT BoxPaintInvalidator {
  private:
   friend class BoxPaintInvalidatorTest;
 
-  bool BackgroundGeometryDependsOnLayoutOverflowRect();
+  bool BackgroundGeometryDependsOnLayoutOverflowRect() const;
   bool BackgroundPaintsOntoScrollingContentsLayer();
   bool ShouldFullyInvalidateBackgroundOnLayoutOverflowChange(
       const LayoutRect& old_layout_overflow,
       const LayoutRect& new_layout_overflow);
+  bool ViewBackgroundShouldFullyInvalidate() const;
 
   enum BackgroundInvalidationType { kNone = 0, kIncremental, kFull };
   BackgroundInvalidationType ComputeBackgroundInvalidation();

third_party/WebKit/Source/core/paint/ViewPaintInvalidator.cpp

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "core/paint/ViewPaintInvalidator.h"
-
-#include "core/layout/LayoutView.h"
-#include "core/paint/BoxPaintInvalidator.h"
-#include "platform/geometry/LayoutSize.h"
-
-namespace blink {
-
-PaintInvalidationReason ViewPaintInvalidator::InvalidatePaint() {
-  InvalidateBackgroundIfNeeded();
-  return BoxPaintInvalidator(view_, context_).InvalidatePaint();
-}
-
-void ViewPaintInvalidator::InvalidateBackgroundIfNeeded() {
-  // Fixed attachment background is handled in LayoutView::layout().
-  // TODO(wangxianzhu): Combine code for fixed-attachment background when we
-  // enable rootLayerScrolling permanently.
-  if (view_.StyleRef().HasEntirelyFixedBackground())
-    return;
-
-  // LayoutView's non-fixed-attachment background is positioned in the
-  // document element.
-  // See https://drafts.csswg.org/css-backgrounds-3/#root-background.
-  Element* document_element = view_.GetDocument().documentElement();
-  if (!document_element)
-    return;
-  const LayoutObject* background_object = document_element->GetLayoutObject();
-  if (!background_object || !background_object->IsBox())
-    return;
-
-  const LayoutBox& background_box = ToLayoutBox(*background_object);
-  LayoutSize old_size = background_box.PreviousSize();
-  LayoutSize new_size = background_box.Size();
-  const auto& background_layers = view_.StyleRef().BackgroundLayers();
-  if ((old_size.Width() != new_size.Width() &&
-       LayoutBox::MustInvalidateFillLayersPaintOnWidthChange(
-           background_layers)) ||
-      (old_size.Height() != new_size.Height() &&
-       LayoutBox::MustInvalidateFillLayersPaintOnHeightChange(
-           background_layers))) {
-    view_.GetMutableForPainting().SetShouldDoFullPaintInvalidation(
-        PaintInvalidationReason::kBackground);
-  }
-}
-
-}  // namespace blink

third_party/WebKit/Source/core/paint/ViewPaintInvalidator.h

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef ViewPaintInvalidator_h
-#define ViewPaintInvalidator_h
-
-#include "platform/graphics/PaintInvalidationReason.h"
-#include "platform/wtf/Allocator.h"
-
-namespace blink {
-
-class LayoutView;
-struct PaintInvalidatorContext;
-
-class ViewPaintInvalidator {
-  STACK_ALLOCATED();
-
- public:
-  ViewPaintInvalidator(const LayoutView& view,
-                       const PaintInvalidatorContext& context)
-      : view_(view), context_(context) {}
-
-  PaintInvalidationReason InvalidatePaint();
-
- private:
-  void InvalidateBackgroundIfNeeded();
-
-  const LayoutView& view_;
-  const PaintInvalidatorContext& context_;
-};
-
-}  // namespace blink
-
-#endif