[FragmentItem] Remove |NodeForHitTest| from |NGPaintFragment|

It looks like we tried to copy the logic in |LayoutObject::
NodeForHitTest| to |NGPaintFragment|. As part of deprecating
|NGPaintFragment|, this patch moves it to |NGPhysicalFragment|,
using the existing logic in |LayoutObject|.

In future, this logic might be moved to |Node| or something
that represents the box tree. Until then, using the logic in
|LayoutObject| looks most reasonable.

Bug: 982194
Change-Id: Ib6b967dc616714eb2cb1a16585493d106c44c504
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1937953Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719562}

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

@@ -3330,17 +3330,22 @@ bool LayoutObject::HitTestAllPhases(HitTestResult& result,
 }
 
 Node* LayoutObject::NodeForHitTest() const {
-  Node* node = GetNode();
+  if (Node* node = GetNode())
+    return node;
 
   // If we hit the anonymous layoutObjects inside generated content we should
   // actually hit the generated content so walk up to the PseudoElement.
-  if (!node && Parent() && Parent()->IsBeforeOrAfterContent()) {
-    for (LayoutObject* layout_object = Parent(); layout_object && !node;
-         layout_object = layout_object->Parent())
-      node = layout_object->GetNode();
+  if (const LayoutObject* parent = Parent()) {
+    if (parent->IsBeforeOrAfterContent() ||
+        parent->StyleRef().StyleType() == kPseudoIdFirstLetter) {
+      for (; parent; parent = parent->Parent()) {
+        if (Node* node = parent->GetNode())
+          return node;
+      }
+    }
   }
 
-  return node;
+  return nullptr;
 }
 
 void LayoutObject::UpdateHitTestResult(HitTestResult& result,

third_party/blink/renderer/core/layout/ng/ng_physical_fragment.cc

@@ -11,6 +11,7 @@
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_inline_node.h"
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_physical_line_box_fragment.h"
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_physical_text_fragment.h"
+#include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_item.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_block_node.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_fragment_builder.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_physical_box_fragment.h"
@@ -32,6 +33,21 @@ static_assert(sizeof(NGPhysicalFragment) ==
                   sizeof(SameSizeAsNGPhysicalFragment),
               "NGPhysicalFragment should stay small");
 
+const LayoutObject* ListMarkerFromMarkerOrMarkerContent(
+    const LayoutObject* object) {
+  if (object->IsLayoutNGListMarkerIncludingInside())
+    return object;
+
+  // Check if this is a marker content.
+  if (object->IsAnonymous()) {
+    const LayoutObject* parent = object->Parent();
+    if (parent && parent->IsLayoutNGListMarkerIncludingInside())
+      return parent;
+  }
+
+  return nullptr;
+}
+
 bool AppendFragmentOffsetAndSize(const NGPhysicalFragment* fragment,
                                  base::Optional<PhysicalOffset> fragment_offset,
                                  StringBuilder* builder,
@@ -488,6 +504,22 @@ bool NGPhysicalFragment::ShouldPaintDragCaret() const {
   return false;
 }
 
+Node* NGPhysicalFragment::NodeForHitTest() const {
+  if (Node* node = layout_object_->NodeForHitTest())
+    return node;
+
+  // When the fragment is a list marker, return the list item.
+  if (const LayoutObject* marker =
+          ListMarkerFromMarkerOrMarkerContent(layout_object_)) {
+    if (const LayoutNGListItem* list_item =
+            LayoutNGListItem::FromMarker(*marker))
+      return list_item->GetNode();
+    return nullptr;
+  }
+
+  return nullptr;
+}
+
 String NGPhysicalFragment::ToString() const {
   StringBuilder output;
   output.AppendFormat("Type: '%d' Size: '%s'", Type(),

third_party/blink/renderer/core/layout/ng/ng_physical_fragment.h

@@ -202,6 +202,9 @@ class CORE_EXPORT NGPhysicalFragment
   Node* GeneratingNode() const {
     return IsCSSBox() ? layout_object_->GeneratingNode() : nullptr;
   }
+  // The node to return when hit-testing on this fragment. This can be different
+  // from GetNode() when this fragment is content of a pseudo node.
+  Node* NodeForHitTest() const;
 
   // Whether there is a PaintLayer associated with the fragment.
   bool HasLayer() const { return IsCSSBox() && layout_object_->HasLayer(); }

third_party/blink/renderer/core/paint/ng/ng_paint_fragment.cc

@@ -178,40 +178,10 @@ base::Optional<PositionWithAffinity> PositionForPointInChild(
   return base::nullopt;
 }
 
-// ::before, ::after and ::first-letter can be hit test targets.
-bool CanBeHitTestTargetPseudoNode(const Node& node) {
-  auto* pseudo_element = DynamicTo<PseudoElement>(node);
-  if (!pseudo_element)
-    return false;
-  switch (pseudo_element->GetPseudoId()) {
-    case kPseudoIdBefore:
-    case kPseudoIdAfter:
-    case kPseudoIdFirstLetter:
-      return true;
-    default:
-      return false;
-  }
-}
-
 bool IsLastBRInPage(const LayoutObject& layout_object) {
   return layout_object.IsBR() && !layout_object.NextInPreOrder();
 }
 
-const LayoutObject* ListMarkerFromMarkerOrMarkerContent(
-    const LayoutObject* object) {
-  if (object->IsLayoutNGListMarkerIncludingInside())
-    return object;
-
-  // Check if this is a marker content.
-  if (object->IsAnonymous()) {
-    const LayoutObject* parent = object->Parent();
-    if (parent && parent->IsLayoutNGListMarkerIncludingInside())
-      return parent;
-  }
-
-  return nullptr;
-}
-
 }  // namespace
 
 NGPaintFragment::NGPaintFragment(
@@ -1152,44 +1122,6 @@ PositionWithAffinity NGPaintFragment::PositionForPoint(
   return PositionForPointInInlineLevelBox(point);
 }
 
-Node* NGPaintFragment::NodeForHitTest() const {
-  if (GetNode())
-    return GetNode();
-
-  if (PhysicalFragment().IsLineBox())
-    return Parent()->NodeForHitTest();
-
-  // When the fragment is a list marker, return the list item.
-  if (const LayoutObject* object = GetLayoutObject()) {
-    if (const LayoutObject* marker =
-            ListMarkerFromMarkerOrMarkerContent(object)) {
-      if (const LayoutNGListItem* list_item =
-              LayoutNGListItem::FromMarker(*marker))
-        return list_item->GetNode();
-      return nullptr;
-    }
-  }
-
-  for (const NGPaintFragment* runner = Parent(); runner;
-       runner = runner->Parent()) {
-    // When the fragment is inside a ::first-letter, ::before or ::after pseudo
-    // node, return the pseudo node.
-    if (Node* node = runner->GetNode()) {
-      if (CanBeHitTestTargetPseudoNode(*node))
-        return node;
-      return nullptr;
-    }
-
-    // When the fragment is inside a list marker, return the list item.
-    if (runner->GetLayoutObject() &&
-        runner->GetLayoutObject()->IsLayoutNGListMarker()) {
-      return runner->NodeForHitTest();
-    }
-  }
-
-  return nullptr;
-}
-
 String NGPaintFragment::DebugName() const {
   StringBuilder name;
 

third_party/blink/renderer/core/paint/ng/ng_paint_fragment.h

@@ -217,7 +217,7 @@ class CORE_EXPORT NGPaintFragment : public RefCounted<NGPaintFragment>,
 
   // The node to return when hit-testing on this fragment. This can be different
   // from GetNode() when this fragment is content of a pseudo node.
-  Node* NodeForHitTest() const;
+  Node* NodeForHitTest() const { return PhysicalFragment().NodeForHitTest(); }
 
   // Returns true when associated fragment of |layout_object| has line box.
   static bool TryMarkFirstLineBoxDirtyFor(const LayoutObject& layout_object);