Use new downcast helper for LayoutBoxModelObject and LayoutBox in cor…

…e/[f-km-z]*/

* Add MainThreadScrollingReasonsTest::GetScrollableArea() and
  RootScrollerTest::GetScrollableArea() to reduce the number of casts to
  LayoutBoxModelObject.

This CL has no behavior changes.

Bug: 891908
Change-Id: I10d52bff1b228d54f67b7585b0e6c8ff3ba7a51b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2531800
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Auto-Submit: Kent Tamura <tkent@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826574}

third_party/blink/renderer/core/frame/local_frame_view.cc

@@ -686,7 +686,7 @@ bool LocalFrameView::LayoutFromRootObject(LayoutObject& root) {
     }
   }
 
-  ToLayoutBox(root).LayoutSubtreeRoot();
+  To<LayoutBox>(root).LayoutSubtreeRoot();
   return true;
 }
 
@@ -1117,7 +1117,7 @@ void LocalFrameView::RunIntersectionObserverSteps() {
     // Report the main frame's document intersection with itself.
     LayoutObject* layout_object = GetLayoutView();
     IntRect main_frame_dimensions =
-        ToLayoutBox(layout_object)->PixelSnappedLayoutOverflowRect();
+        To<LayoutBox>(layout_object)->PixelSnappedLayoutOverflowRect();
     GetFrame().Client()->OnMainFrameIntersectionChanged(WebRect(
         0, 0, main_frame_dimensions.Width(), main_frame_dimensions.Height()));
   }
@@ -1284,7 +1284,7 @@ bool LocalFrameView::RequiresMainThreadScrollingForBackgroundAttachmentFixed()
     return true;
 
   const auto* object =
-      ToLayoutBoxModelObject(*background_attachment_fixed_objects_.begin());
+      To<LayoutBoxModelObject>(*background_attachment_fixed_objects_.begin());
   // We should not add such object in the set.
   DCHECK(!object->BackgroundTransfersToView());
   // If the background is viewport background and it paints onto the main
@@ -1435,7 +1435,7 @@ bool LocalFrameView::InvalidateViewportConstrainedObjects() {
     DCHECK(layout_object->StyleRef().HasViewportConstrainedPosition() ||
            layout_object->StyleRef().HasStickyConstrainedPosition());
     DCHECK(layout_object->HasLayer());
-    PaintLayer* layer = ToLayoutBoxModelObject(layout_object)->Layer();
+    PaintLayer* layer = To<LayoutBoxModelObject>(layout_object)->Layer();
 
     if (!RuntimeEnabledFeatures::CompositeAfterPaintEnabled()) {
       DisableCompositingQueryAsserts disabler;
@@ -1628,10 +1628,10 @@ static inline void RemoveFloatingObjectsForSubtreeRoot(LayoutObject& root) {
 }
 
 static bool PrepareOrthogonalWritingModeRootForLayout(LayoutObject& root) {
-  DCHECK(root.IsBox() && ToLayoutBox(root).IsOrthogonalWritingModeRoot());
+  DCHECK(To<LayoutBox>(root).IsOrthogonalWritingModeRoot());
   if (!root.NeedsLayout() || root.IsOutOfFlowPositioned() ||
       root.IsColumnSpanAll() || root.StyleRef().LogicalHeight().IsSpecified() ||
-      ToLayoutBox(root).IsGridItem() || root.IsTablePart())
+      To<LayoutBox>(root).IsGridItem() || root.IsTablePart())
     return false;
 
   if (RuntimeEnabledFeatures::LayoutNGEnabled()) {
@@ -1646,7 +1646,7 @@ static bool PrepareOrthogonalWritingModeRootForLayout(LayoutObject& root) {
     // which called |RunLegacyLayout()|. This parent not only needs to run
     // pre-layout, but also clearing |NeedsLayout()| without updating
     // |CachedLayoutResult| is harmful.
-    if (const auto* box = ToLayoutBoxOrNull(&root)) {
+    if (const auto* box = DynamicTo<LayoutBox>(root)) {
       if (box->GetCachedLayoutResult())
         return false;
     }
@@ -4556,10 +4556,11 @@ bool LocalFrameView::HasVisibleSlowRepaintViewportConstrainedObjects() const {
   if (!ViewportConstrainedObjects())
     return false;
   for (const LayoutObject* layout_object : *ViewportConstrainedObjects()) {
-    DCHECK(layout_object->IsBoxModelObject() && layout_object->HasLayer());
+    DCHECK(layout_object->HasLayer());
     DCHECK(layout_object->StyleRef().GetPosition() == EPosition::kFixed ||
            layout_object->StyleRef().GetPosition() == EPosition::kSticky);
-    if (ToLayoutBoxModelObject(layout_object)->IsSlowRepaintConstrainedObject())
+    if (To<LayoutBoxModelObject>(layout_object)
+            ->IsSlowRepaintConstrainedObject())
       return true;
   }
   return false;

third_party/blink/renderer/core/frame/local_frame_view_test.cc

@@ -163,8 +163,7 @@ TEST_F(LocalFrameViewTest,
     <div class='container'><div id='sticky'></div></div>
   )HTML");
 
-  LayoutBoxModelObject* sticky = ToLayoutBoxModelObject(
-      GetDocument().getElementById("sticky")->GetLayoutObject());
+  auto* sticky = To<LayoutBoxModelObject>(GetLayoutObjectByElementId("sticky"));
 
   // Deliberately invalidate the ancestor overflow layer. This approximates
   // http://crbug.com/696173, in which the ancestor overflow layer can be null

third_party/blink/renderer/core/frame/web_frame_test.cc

@@ -7935,8 +7935,8 @@ TEST_F(WebFrameTest, FullscreenLayerSize) {
   EXPECT_EQ(div_fullscreen, Fullscreen::FullscreenElementFrom(*document));
 
   // Verify that the element is sized to the viewport.
-  LayoutBox* fullscreen_layout_object =
-      ToLayoutBox(div_fullscreen->GetLayoutObject());
+  auto* fullscreen_layout_object =
+      To<LayoutBox>(div_fullscreen->GetLayoutObject());
   EXPECT_EQ(viewport_width, fullscreen_layout_object->LogicalWidth().ToInt());
   EXPECT_EQ(viewport_height, fullscreen_layout_object->LogicalHeight().ToInt());
 
@@ -8088,8 +8088,8 @@ TEST_F(WebFrameTest, FullscreenSubframe) {
   UpdateAllLifecyclePhases(web_view_impl);
 
   // Verify that the element is sized to the viewport.
-  LayoutBox* fullscreen_layout_object =
-      ToLayoutBox(div_fullscreen->GetLayoutObject());
+  auto* fullscreen_layout_object =
+      To<LayoutBox>(div_fullscreen->GetLayoutObject());
   EXPECT_EQ(viewport_width, fullscreen_layout_object->LogicalWidth().ToInt());
   EXPECT_EQ(viewport_height, fullscreen_layout_object->LogicalHeight().ToInt());
 
@@ -8506,7 +8506,7 @@ TEST_F(WebFrameTest, WebXrImmersiveOverlay) {
             SK_AlphaTRANSPARENT);
 
   GraphicsLayer* inner_layer =
-      ToLayoutBoxModelObject(
+      To<LayoutBoxModelObject>(
           frame->GetDocument()->getElementById("inner")->GetLayoutObject())
           ->Layer()
           ->GetCompositedLayerMapping()
@@ -8546,12 +8546,12 @@ TEST_F(WebFrameTest, LayoutBlockPercentHeightDescendants) {
   Document* document = web_view->MainFrameImpl()->GetFrame()->GetDocument();
   LayoutBlock* container =
       To<LayoutBlock>(document->getElementById("container")->GetLayoutObject());
-  LayoutBox* percent_height_in_anonymous =
-      ToLayoutBox(document->getElementById("percent-height-in-anonymous")
-                      ->GetLayoutObject());
-  LayoutBox* percent_height_direct_child =
-      ToLayoutBox(document->getElementById("percent-height-direct-child")
-                      ->GetLayoutObject());
+  auto* percent_height_in_anonymous =
+      To<LayoutBox>(document->getElementById("percent-height-in-anonymous")
+                        ->GetLayoutObject());
+  auto* percent_height_direct_child =
+      To<LayoutBox>(document->getElementById("percent-height-direct-child")
+                        ->GetLayoutObject());
 
   EXPECT_TRUE(
       container->HasPercentHeightDescendant(percent_height_in_anonymous));

third_party/blink/renderer/core/frame/web_frame_widget_base.cc

@@ -155,7 +155,7 @@ viz::FrameSinkId GetRemoteFrameSinkId(const HitTestResult& result) {
     return viz::FrameSinkId();
 
   IntPoint local_point = RoundedIntPoint(result.LocalPoint());
-  if (!ToLayoutBox(object)->ComputedCSSContentBoxRect().Contains(local_point))
+  if (!To<LayoutBox>(object)->ComputedCSSContentBoxRect().Contains(local_point))
     return viz::FrameSinkId();
 
   return remote_frame->GetFrameSinkId();
@@ -461,10 +461,8 @@ viz::FrameSinkId WebFrameWidgetBase::GetFrameSinkIdAtPoint(
   if (remote_frame_sink_id.is_valid()) {
     FloatPoint local_point = FloatPoint(result.LocalPoint());
     LayoutObject* object = result.GetLayoutObject();
-    if (object->IsBox()) {
-      LayoutBox* box = ToLayoutBox(object);
+    if (auto* box = DynamicTo<LayoutBox>(object))
       local_point.MoveBy(-FloatPoint(box->PhysicalContentBoxOffset()));
-    }
 
     *local_point_in_dips =
         widget_base_->BlinkSpaceToDIPs(gfx::PointF(local_point));

third_party/blink/renderer/core/html/canvas/html_canvas_element_test.cc

@@ -21,15 +21,16 @@ TEST_F(HTMLCanvasElementTest, CreateLayerUpdatesCompositing) {
 
   SetBodyInnerHTML("<canvas id='canvas'></canvas>");
   auto* canvas = To<HTMLCanvasElement>(GetDocument().getElementById("canvas"));
-  auto* layer = ToLayoutBoxModelObject(canvas->GetLayoutObject())->Layer();
+  auto* layer = GetPaintLayerByElementId("canvas");
   ASSERT_TRUE(layer);
   EXPECT_EQ(CompositingReason::kNone, layer->DirectCompositingReasons());
 
   EXPECT_FALSE(layer->NeedsCompositingInputsUpdate());
   canvas->CreateLayer();
   EXPECT_TRUE(layer->NeedsCompositingInputsUpdate());
   UpdateAllLifecyclePhasesForTest();
-  ASSERT_EQ(layer, ToLayoutBoxModelObject(canvas->GetLayoutObject())->Layer());
+  ASSERT_EQ(layer,
+            To<LayoutBoxModelObject>(canvas->GetLayoutObject())->Layer());
   EXPECT_EQ(CompositingReason::kCanvas, layer->DirectCompositingReasons());
 }
 

third_party/blink/renderer/core/html/forms/external_popup_menu.cc

@@ -97,10 +97,9 @@ bool ExternalPopupMenu::ShowInternal() {
     LayoutObject* layout_object = owner_element_->GetLayoutObject();
     if (!layout_object || !layout_object->IsBox())
       return false;
+    auto* box = To<LayoutBox>(layout_object);
     IntRect rect = EnclosingIntRect(
-        ToLayoutBox(layout_object)
-            ->LocalToAbsoluteRect(
-                ToLayoutBox(layout_object)->PhysicalBorderBoxRect()));
+        box->LocalToAbsoluteRect(box->PhysicalBorderBoxRect()));
     IntRect rect_in_viewport = local_frame_->View()->FrameToViewport(rect);
     float scale_for_emulation = WebLocalFrameImpl::FromFrame(local_frame_)
                                     ->LocalRootFrameWidget()

third_party/blink/renderer/core/html/forms/html_field_set_element.cc

@@ -131,7 +131,7 @@ LayoutBox* HTMLFieldSetElement::GetLayoutBoxForScrolling() const {
     return HTMLFormControlElement::GetLayoutBoxForScrolling();
   LayoutObject* child = layout_box->SlowFirstChild();
   if (child && child->IsAnonymous())
-    return ToLayoutBox(child);
+    return To<LayoutBox>(child);
   return HTMLFormControlElement::GetLayoutBoxForScrolling();
 }
 

third_party/blink/renderer/core/html/forms/slider_thumb_element.cc

@@ -114,7 +114,7 @@ void SliderThumbElement::SetPositionFromPoint(const LayoutPoint& point) {
   LayoutUnit track_size;
   LayoutUnit position;
   LayoutUnit current_position;
-  const LayoutBox* input_box = ToLayoutBox(input_object);
+  const auto* input_box = To<LayoutBox>(input_object);
   PhysicalOffset thumb_offset =
       thumb_box->LocalToAncestorPoint(PhysicalOffset(), input_box) -
       track_box->LocalToAncestorPoint(PhysicalOffset(), input_box);

third_party/blink/renderer/core/html/html_anchor_element.cc

@@ -165,7 +165,7 @@ static void AppendServerMapMousePosition(StringBuilder& url, Event* event) {
   // The origin (0,0) is at the upper left of the content area, inside the
   // padding and border.
   map_point -=
-      FloatSize(ToLayoutBox(layout_object)->PhysicalContentBoxOffset());
+      FloatSize(To<LayoutBox>(layout_object)->PhysicalContentBoxOffset());
 
   // CSS zoom is not reflected in the map coordinates.
   float scale_factor = 1 / layout_object->Style()->EffectiveZoom();

third_party/blink/renderer/core/html/html_area_element.cc

@@ -114,8 +114,8 @@ Path HTMLAreaElement::GetPath(const LayoutObject* container_object) const {
     Path path;
     // No need to zoom because it is already applied in
     // containerObject->borderBoxRect().
-    if (container_object->IsBox())
-      path.AddRect(FloatRect(ToLayoutBox(container_object)->BorderBoxRect()));
+    if (const auto* box = DynamicTo<LayoutBox>(container_object))
+      path.AddRect(FloatRect(box->BorderBoxRect()));
     path_ = nullptr;
     return path;
   }

third_party/blink/renderer/core/html/media/html_video_element_test.cc

@@ -158,7 +158,7 @@ TEST_F(HTMLVideoElementTest, ChangeLayerNeedsCompositingUpdate) {
   SetFakeCcLayer(layer1.get());
   ASSERT_TRUE(video()->GetLayoutObject()->HasLayer());
   auto* paint_layer =
-      ToLayoutBoxModelObject(video()->GetLayoutObject())->Layer();
+      To<LayoutBoxModelObject>(video()->GetLayoutObject())->Layer();
   EXPECT_TRUE(paint_layer->NeedsCompositingInputsUpdate());
   UpdateAllLifecyclePhasesForTest();
   EXPECT_FALSE(paint_layer->NeedsCompositingInputsUpdate());

third_party/blink/renderer/core/html/track/text_track_container.cc

@@ -127,7 +127,7 @@ void TextTrackContainer::UpdateDefaultFontSize(
   // for lack of per-spec vh/vw support) but the whole media element is used
   // for cue rendering. This is inconsistent. See also the somewhat related
   // spec bug: https://www.w3.org/Bugs/Public/show_bug.cgi?id=28105
-  LayoutSize video_size = ToLayoutBox(media_layout_object)->ContentSize();
+  LayoutSize video_size = To<LayoutBox>(media_layout_object)->ContentSize();
   LayoutUnit smallest_dimension =
       std::min(video_size.Height(), video_size.Width());
   float font_size = smallest_dimension * 0.05f;

third_party/blink/renderer/core/input/scroll_manager.cc

@@ -279,7 +279,7 @@ bool ScrollManager::LogicalScroll(mojom::blink::ScrollDirection direction,
     Node* scroll_chain_node = DOMNodeIds::NodeForId(scroll_chain.TakeLast());
     DCHECK(scroll_chain_node);
 
-    LayoutBox* box = ToLayoutBox(scroll_chain_node->GetLayoutObject());
+    auto* box = To<LayoutBox>(scroll_chain_node->GetLayoutObject());
     DCHECK(box);
 
     ScrollDirectionPhysical physical_direction =

third_party/blink/renderer/core/inspector/inspector_highlight.cc

@@ -206,11 +206,11 @@ const ShapeOutsideInfo* ShapeOutsideInfoForNode(Node* node,
                                                 FloatQuad* bounds) {
   LayoutObject* layout_object = node->GetLayoutObject();
   if (!layout_object || !layout_object->IsBox() ||
-      !ToLayoutBox(layout_object)->GetShapeOutsideInfo())
+      !To<LayoutBox>(layout_object)->GetShapeOutsideInfo())
     return nullptr;
 
   LocalFrameView* containing_view = node->GetDocument().View();
-  LayoutBox* layout_box = ToLayoutBox(layout_object);
+  auto* layout_box = To<LayoutBox>(layout_object);
   const ShapeOutsideInfo* shape_outside_info =
       layout_box->GetShapeOutsideInfo();
 
@@ -847,7 +847,7 @@ Vector<Vector<PhysicalRect>> GetFlexLinesAndItems(LayoutBox* layout_box,
       PhysicalOffset fragment_offset = child.Offset();
 
       const LayoutObject* object = child_fragment->GetLayoutObject();
-      const LayoutBox* box = ToLayoutBox(object);
+      const auto* box = To<LayoutBox>(object);
       PhysicalRect item_rect =
           PhysicalRect(fragment_offset.left - box->MarginLeft(),
                        fragment_offset.top - box->MarginTop(),
@@ -878,7 +878,7 @@ std::unique_ptr<protocol::DictionaryValue> BuildFlexInfo(
     float scale) {
   LocalFrameView* containing_view = node->GetDocument().View();
   LayoutObject* layout_object = node->GetLayoutObject();
-  LayoutBox* layout_box = ToLayoutBox(layout_object);
+  auto* layout_box = To<LayoutBox>(layout_object);
   DCHECK(layout_object);
   bool is_horizontal = IsHorizontalFlex(layout_object);
 
@@ -1247,7 +1247,7 @@ bool InspectorHighlightBase::BuildNodeQuads(Node* node,
     border_box = text_rect;
     margin_box = text_rect;
   } else if (layout_object->IsBox()) {
-    LayoutBox* layout_box = ToLayoutBox(layout_object);
+    auto* layout_box = To<LayoutBox>(layout_object);
     content_box = layout_box->PhysicalContentBoxRect();
 
     // Include scrollbars and gutters in the padding highlight.
@@ -1661,9 +1661,7 @@ bool InspectorHighlight::GetBoxModel(
 
   IntRect bounding_box =
       view->ConvertToRootFrame(layout_object->AbsoluteBoundingBoxRect());
-  LayoutBoxModelObject* model_object =
-      layout_object->IsBoxModelObject() ? ToLayoutBoxModelObject(layout_object)
-                                        : nullptr;
+  auto* model_object = DynamicTo<LayoutBoxModelObject>(layout_object);
 
   *model =
       protocol::DOM::BoxModel::create()

third_party/blink/renderer/core/intersection_observer/intersection_geometry.cc

@@ -89,9 +89,9 @@ PhysicalRect InitializeRootRect(const LayoutObject* root,
     // we can zoom out to fit the entire element width.
     result = layout_view->OverflowClipRect(PhysicalOffset());
   } else if (root->IsBox() && root->IsScrollContainer()) {
-    result = ToLayoutBox(root)->PhysicalContentBoxRect();
+    result = To<LayoutBox>(root)->PhysicalContentBoxRect();
   } else {
-    result = PhysicalRect(ToLayoutBoxModelObject(root)->BorderBoundingBox());
+    result = PhysicalRect(To<LayoutBoxModelObject>(root)->BorderBoundingBox());
   }
   ApplyMargin(result, margin, root->StyleRef().EffectiveZoom());
   return result;
@@ -107,7 +107,7 @@ PhysicalRect InitializeTargetRect(const LayoutObject* target,
       target->IsLayoutEmbeddedContent()) {
     result = To<LayoutEmbeddedContent>(target)->ReplacedContentRect();
   } else if (target->IsBox()) {
-    result = PhysicalRect(ToLayoutBoxModelObject(target)->BorderBoundingBox());
+    result = PhysicalRect(To<LayoutBox>(target)->BorderBoundingBox());
   } else if (target->IsLayoutInline()) {
     result = target->AbsoluteToLocalRect(
         PhysicalRect::EnclosingRect(target->AbsoluteBoundingBoxFloatRect()));
@@ -446,7 +446,7 @@ bool IntersectionGeometry::ClipToRoot(const LayoutObject* root,
   // TODO(szager): the writing mode flipping needs a test.
   const LayoutBox* local_ancestor = nullptr;
   if (!RootIsImplicit() || root->GetDocument().IsInMainFrame())
-    local_ancestor = ToLayoutBox(root);
+    local_ancestor = To<LayoutBox>(root);
 
   unsigned flags = kDefaultVisualRectFlags | kEdgeInclusive |
                    kDontApplyMainFrameOverflowClip;

third_party/blink/renderer/core/page/autoscroll_controller.cc

@@ -123,9 +123,7 @@ void AutoscrollController::StartAutoscrollForSelection(
   if (!scrollable)
     return;
 
-  pressed_layout_object_ = layout_object && layout_object->IsBox()
-                               ? ToLayoutBox(layout_object)
-                               : nullptr;
+  pressed_layout_object_ = DynamicTo<LayoutBox>(layout_object);
   autoscroll_type_ = kAutoscrollForSelection;
   autoscroll_layout_object_ = scrollable;
   ScheduleMainThreadAnimation();
@@ -158,13 +156,10 @@ void AutoscrollController::UpdateAutoscrollLayoutObject() {
   LayoutObject* layout_object = autoscroll_layout_object_;
 
   while (layout_object && !(layout_object->IsBox() &&
-                            ToLayoutBox(layout_object)->CanAutoscroll()))
+                            To<LayoutBox>(layout_object)->CanAutoscroll()))
     layout_object = layout_object->Parent();
 
-  autoscroll_layout_object_ = layout_object && layout_object->IsBox()
-                                  ? ToLayoutBox(layout_object)
-                                  : nullptr;
-
+  autoscroll_layout_object_ = DynamicTo<LayoutBox>(layout_object);
   if (!autoscroll_layout_object_)
     autoscroll_type_ = kNoAutoscroll;
 }

third_party/blink/renderer/core/page/print_context.cc

@@ -38,9 +38,7 @@ namespace {
 LayoutBoxModelObject* EnclosingBoxModelObject(LayoutObject* object) {
   while (object && !object->IsBoxModelObject())
     object = object->Parent();
-  if (!object)
-    return nullptr;
-  return ToLayoutBoxModelObject(object);
+  return To<LayoutBoxModelObject>(object);
 }
 
 bool IsCoordinateInPage(int top, int left, const IntRect& page) {