[LayoutNG] Refactor dialog positioning into NG

Bug: 740993
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I5a0dd12b81fd300b42bfae0c7a5432ffadd6fb39
Reviewed-on: https://chromium-review.googlesource.com/1110488Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Aleks Totic <atotic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569532}

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

@@ -55,6 +55,7 @@
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_line_height_metrics.h"
 #include "third_party/blink/renderer/core/layout/ng/layout_ng_block_flow.h"
 #include "third_party/blink/renderer/core/layout/ng/legacy_layout_tree_walking.h"
+#include "third_party/blink/renderer/core/layout/ng/ng_absolute_utils.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_box_fragment.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_fragmentation_utils.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_layout_result.h"
@@ -4603,44 +4604,9 @@ LayoutBlockFlow::LayoutBlockFlowRareData& LayoutBlockFlow::EnsureRareData() {
   return *rare_data_;
 }
 
-base::Optional<LayoutUnit> LayoutBlockFlow::ComputeDialogYPosition(
-    LayoutUnit height) const {
-  DCHECK(IsHTMLDialogElement(GetNode()));
-  HTMLDialogElement* dialog = ToHTMLDialogElement(GetNode());
-  if (dialog->GetCenteringMode() == HTMLDialogElement::kNotCentered)
-    return base::nullopt;
-
-  bool can_center_dialog = (Style()->GetPosition() == EPosition::kAbsolute ||
-                            Style()->GetPosition() == EPosition::kFixed) &&
-                           Style()->HasAutoTopAndBottom();
-
-  if (dialog->GetCenteringMode() == HTMLDialogElement::kCentered) {
-    if (can_center_dialog)
-      return dialog->CenteredPosition();
-    return base::nullopt;
-  }
-
-  DCHECK_EQ(dialog->GetCenteringMode(), HTMLDialogElement::kNeedsCentering);
-  if (!can_center_dialog) {
-    dialog->SetNotCentered();
-    return base::nullopt;
-  }
-
-  auto* scrollable_area = GetDocument().View()->LayoutViewport();
-  LayoutUnit top =
-      LayoutUnit((Style()->GetPosition() == EPosition::kFixed)
-                     ? 0
-                     : scrollable_area->ScrollOffsetInt().Height());
-
-  int visible_height = GetDocument().View()->Height();
-  if (height < visible_height)
-    top += (visible_height - height) / 2;
-  dialog->SetCentered(top);
-  return top;
-}
-
 void LayoutBlockFlow::PositionDialog() {
-  base::Optional<LayoutUnit> y = ComputeDialogYPosition(Size().Height());
+  base::Optional<LayoutUnit> y =
+      ComputeAbsoluteDialogYPosition(*this, Size().Height());
   if (y.has_value())
     SetY(y.value());
 }

third_party/blink/renderer/core/layout/layout_block_flow.h

@@ -808,8 +808,6 @@ class CORE_EXPORT LayoutBlockFlow : public LayoutBlock {
 
   bool ShouldTruncateOverflowingText() const;
 
-  base::Optional<LayoutUnit> ComputeDialogYPosition(LayoutUnit height) const;
-
   int GetLayoutPassCountForTesting();
 
  protected:

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

@@ -4,9 +4,12 @@
 
 #include "third_party/blink/renderer/core/layout/ng/ng_absolute_utils.h"
 
+#include "third_party/blink/renderer/core/html/html_dialog_element.h"
+#include "third_party/blink/renderer/core/layout/layout_object.h"
 #include "third_party/blink/renderer/core/layout/ng/geometry/ng_static_position.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_constraint_space.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_length_utils.h"
+#include "third_party/blink/renderer/core/paint/paint_layer_scrollable_area.h"
 #include "third_party/blink/renderer/core/style/computed_style.h"
 #include "third_party/blink/renderer/platform/length_functions.h"
 
@@ -495,6 +498,50 @@ bool AbsoluteNeedsChildInlineSize(const ComputedStyle& style) {
     return AbsoluteVerticalNeedsEstimate(style);
 }
 
+base::Optional<LayoutUnit> ComputeAbsoluteDialogYPosition(
+    const LayoutObject& dialog,
+    LayoutUnit height) {
+  if (!IsHTMLDialogElement(dialog.GetNode()))
+    return base::nullopt;
+
+  // This code implements <dialog> static position spec.
+  // //
+  // https://html.spec.whatwg.org/multipage/interactive-elements.html#the-dialog-element
+  HTMLDialogElement* dialog_node = ToHTMLDialogElement(dialog.GetNode());
+  if (dialog_node->GetCenteringMode() == HTMLDialogElement::kNotCentered)
+    return base::nullopt;
+
+  bool can_center_dialog =
+      (dialog.Style()->GetPosition() == EPosition::kAbsolute ||
+       dialog.Style()->GetPosition() == EPosition::kFixed) &&
+      dialog.Style()->HasAutoTopAndBottom();
+
+  if (dialog_node->GetCenteringMode() == HTMLDialogElement::kCentered) {
+    if (can_center_dialog)
+      return dialog_node->CenteredPosition();
+    return base::nullopt;
+  }
+
+  DCHECK_EQ(dialog_node->GetCenteringMode(),
+            HTMLDialogElement::kNeedsCentering);
+  if (!can_center_dialog) {
+    dialog_node->SetNotCentered();
+    return base::nullopt;
+  }
+
+  auto* scrollable_area = dialog.GetDocument().View()->LayoutViewport();
+  LayoutUnit top =
+      LayoutUnit((dialog.Style()->GetPosition() == EPosition::kFixed)
+                     ? 0
+                     : scrollable_area->ScrollOffsetInt().Height());
+
+  int visible_height = dialog.GetDocument().View()->Height();
+  if (height < visible_height)
+    top += (visible_height - height) / 2;
+  dialog_node->SetCentered(top);
+  return top;
+}
+
 NGAbsolutePhysicalPosition ComputePartialAbsoluteWithChildInlineSize(
     const NGConstraintSpace& space,
     const ComputedStyle& style,

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

@@ -15,6 +15,7 @@
 namespace blink {
 
 class ComputedStyle;
+class LayoutObject;
 class NGConstraintSpace;
 struct NGStaticPosition;
 
@@ -24,6 +25,13 @@ struct CORE_EXPORT NGAbsolutePhysicalPosition {
   String ToString() const;
 };
 
+// Implements <dialog> special case abspos static positining.
+// Returns new dialog top position if layout_dialog requires
+// <dialog> abspos centering.
+CORE_EXPORT base::Optional<LayoutUnit> ComputeAbsoluteDialogYPosition(
+    const LayoutObject& layout_dialog,
+    LayoutUnit height);
+
 // The following routines implement absolute size resolution algorithm.
 // https://www.w3.org/TR/css-position-3/#abs-non-replaced-width
 //

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

@@ -4,8 +4,6 @@
 
 #include "third_party/blink/renderer/core/layout/ng/ng_out_of_flow_layout_part.h"
 
-#include "third_party/blink/renderer/core/html/html_dialog_element.h"
-#include "third_party/blink/renderer/core/layout/layout_block_flow.h"
 #include "third_party/blink/renderer/core/layout/layout_object.h"
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_physical_line_box_fragment.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_absolute_utils.h"
@@ -379,18 +377,14 @@ scoped_refptr<NGLayoutResult> NGOutOfFlowLayoutPart::LayoutDescendant(
       container_info.default_container_offset.inline_offset;
   offset->block_offset += container_info.default_container_offset.block_offset;
 
-  LayoutObject* layout_object = descendant.node.GetLayoutObject();
-  if (IsHTMLDialogElement(layout_object->GetNode())) {
-    base::Optional<LayoutUnit> y =
-        ToLayoutBlockFlow(layout_object)
-            ->ComputeDialogYPosition(
-                layout_result->PhysicalFragment()->Size().height);
-    if (y.has_value()) {
-      if (IsHorizontalWritingMode(container_writing_mode))
-        offset->block_offset = y.value();
-      else
-        offset->inline_offset = y.value();
-    }
+  base::Optional<LayoutUnit> y = ComputeAbsoluteDialogYPosition(
+      *descendant.node.GetLayoutObject(),
+      layout_result->PhysicalFragment()->Size().height);
+  if (y.has_value()) {
+    if (IsHorizontalWritingMode(container_writing_mode))
+      offset->block_offset = y.value();
+    else
+      offset->inline_offset = y.value();
   }
 
   return layout_result;