[NGFragmentItem] Fix hit test on position:relative inline element

This patch fixes hit test on position:relative inline element by changing
|NGInlineCursor::PositionForPointInInlineBox()| and
|LayoutInline::NodeAtPoint()| with descendants to pass assertions in following
tests:
 - All/LayoutViewHitTestTest.HitTestHorizontal/*
 - All/LayoutViewHitTestTest.HitTestVerticalLR/*
 - All/ParameterizedLayoutInlineTest.MultilineRelativePositionedHitTest/1

This patch also changes |LayoutViewHitTestTest| class to check whether LayoutNG
is enabled or disabled by |RuntimeEnabledFlag| instead of gTest's parameter for
ease of working with |LayoutNGFragmentItem| runtime enabled feature.

Note: Changes of |LayoutInline::NodeAtPoint()| is brought by
http://crrev.com/c/2109575.

Bug: 982194
Change-Id: I5d13542a2f57ca8ddd9dcf61a90f3ebbe4b2e0da
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2104812
Commit-Queue: Koji Ishii <kojii@chromium.org>
Auto-Submit: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751910}

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

@@ -1081,7 +1081,7 @@ bool LayoutInline::NodeAtPoint(HitTestResult& result,
           accumulated_offset + item.OffsetInContainerBlock();
       if (NGBoxFragmentPainter(cursor, item, *box_fragment)
               .NodeAtPoint(result, hit_test_location, child_offset,
-                           hit_test_action))
+                           accumulated_offset, hit_test_action))
         return true;
     }
     return false;

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

@@ -74,11 +74,11 @@ class LayoutViewHitTestTest : public testing::WithParamInterface<HitTestConfig>,
                               public RenderingTest {
  public:
   LayoutViewHitTestTest()
-      : ScopedLayoutNGForTest(LayoutNG()),
+      : ScopedLayoutNGForTest(GetParam().layout_ng),
         RenderingTest(MakeGarbageCollected<SingleChildLocalFrameClient>()) {}
 
  protected:
-  bool LayoutNG() { return GetParam().layout_ng; }
+  bool LayoutNG() { return RuntimeEnabledFeatures::LayoutNGEnabled(); }
   bool IsAndroidOrWindowsEditingBehavior() {
     // TODO(crbug.com/971414): For now LayoutNG always uses Android/Windows
     // behavior for ShouldMoveCaretToHorizontalBoundaryWhenPastTopOrBottom().

third_party/blink/renderer/core/layout/ng/inline/ng_inline_cursor.cc

@@ -736,7 +736,8 @@ PositionWithAffinity NGInlineCursor::PositionForPointInInlineBox(
   }
   const NGFragmentItem* container = CurrentItem();
   DCHECK(container);
-  DCHECK_EQ(container->Type(), NGFragmentItem::kLine);
+  DCHECK(container->Type() == NGFragmentItem::kLine ||
+         container->Type() == NGFragmentItem::kBox);
   const ComputedStyle& container_style = container->Style();
   const WritingMode writing_mode = container_style.GetWritingMode();
   const TextDirection direction = container_style.Direction();
@@ -802,6 +803,8 @@ PositionWithAffinity NGInlineCursor::PositionForPointInInlineBox(
     if (const PositionWithAffinity child_position =
             descendants.PositionForPointInChild(point, *closest_child_after))
       return child_position;
+    // TODO(yosin): we should do like "closest_child_before" once we have a
+    // case.
   }
 
   if (closest_child_before) {
@@ -809,6 +812,11 @@ PositionWithAffinity NGInlineCursor::PositionForPointInInlineBox(
     if (const PositionWithAffinity child_position =
             descendants.PositionForPointInChild(point, *closest_child_before))
       return child_position;
+    if (closest_child_before->BoxFragment()) {
+      // LayoutViewHitTest.HitTestHorizontal "Top-right corner (outside) of div"
+      // reach here.
+      return descendants.PositionForPointInInlineBox(point);
+    }
   }
 
   return PositionWithAffinity();

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

@@ -1659,6 +1659,16 @@ bool NGBoxFragmentPainter::NodeAtPoint(HitTestResult& result,
   return NodeAtPoint(hit_test, physical_offset);
 }
 
+bool NGBoxFragmentPainter::NodeAtPoint(HitTestResult& result,
+                                       const HitTestLocation& hit_test_location,
+                                       const PhysicalOffset& physical_offset,
+                                       const PhysicalOffset& inline_root_offset,
+                                       HitTestAction action) {
+  HitTestContext hit_test(action, hit_test_location, inline_root_offset,
+                          &result);
+  return NodeAtPoint(hit_test, physical_offset);
+}
+
 bool NGBoxFragmentPainter::NodeAtPoint(const HitTestContext& hit_test,
                                        const PhysicalOffset& physical_offset) {
   const NGPhysicalBoxFragment& fragment = PhysicalFragment();

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

@@ -60,6 +60,11 @@ class NGBoxFragmentPainter : public BoxPainterBase {
                    const HitTestLocation& hit_test_location,
                    const PhysicalOffset& physical_offset,
                    HitTestAction);
+  bool NodeAtPoint(HitTestResult&,
+                   const HitTestLocation& hit_test_location,
+                   const PhysicalOffset& physical_offset,
+                   const PhysicalOffset& inline_root_offset,
+                   HitTestAction);
 
   bool HitTestAllPhases(HitTestResult&,
                         const HitTestLocation&,