[LayoutNG] NGPhysicalFragment size reduction and warning

This patch reduces the size of NGPhysicalFragment by:
* NGPhysicalFragment by pointer, by removing virtual
  functions.
* NGPhysicalTextFragment by a word, by moving flags to
  NGPhysicalFragment.
* NGPhysicalTextFragment::EndEffect() is no longer used
  and that removed.

Also adds size warning to all subclasses.

Currently, NGPhysicalFragment has 13 bits in flags, plus
5 bits for its subclasses, 18 bits total.

Bug: 591099
Change-Id: I189f691c1976da1eb1223ac9c782e02567038310
Reviewed-on: https://chromium-review.googlesource.com/c/1329703
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607159}

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

@@ -11,6 +11,18 @@
 
 namespace blink {
 
+namespace {
+
+struct SameSizeAsNGPhysicalLineBoxFragment : NGPhysicalContainerFragment {
+  NGLineHeightMetrics metrics;
+};
+
+static_assert(sizeof(NGPhysicalLineBoxFragment) ==
+                  sizeof(SameSizeAsNGPhysicalLineBoxFragment),
+              "NGPhysicalLineBoxFragment should stay small");
+
+}  // namespace
+
 scoped_refptr<const NGPhysicalLineBoxFragment>
 NGPhysicalLineBoxFragment::Create(NGLineBoxFragmentBuilder* builder) {
   // We store the children list inline in the fragment as a flexible

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

@@ -18,6 +18,16 @@ namespace blink {
 
 namespace {
 
+struct SameSizeAsNGPhysicalTextFragment : NGPhysicalFragment {
+  void* pointers[2];
+  NGPhysicalOffsetRect rect;
+  unsigned offsets[2];
+};
+
+static_assert(sizeof(NGPhysicalTextFragment) ==
+                  sizeof(SameSizeAsNGPhysicalTextFragment),
+              "NGPhysicalTextFragment should stay small");
+
 inline bool IsPhysicalTextFragmentAnonymousText(
     const LayoutObject* layout_object) {
   if (!layout_object)
@@ -55,7 +65,6 @@ NGPhysicalTextFragment::NGPhysicalTextFragment(
     unsigned end_offset,
     NGPhysicalSize size,
     NGLineOrientation line_orientation,
-    NGTextEndEffect end_effect,
     scoped_refptr<const ShapeResultView> shape_result)
     : NGPhysicalFragment(layout_object,
                          style,
@@ -66,11 +75,11 @@ NGPhysicalTextFragment::NGPhysicalTextFragment(
       text_(text),
       start_offset_(start_offset),
       end_offset_(end_offset),
-      shape_result_(shape_result),
-      line_orientation_(static_cast<unsigned>(line_orientation)),
-      end_effect_(static_cast<unsigned>(end_effect)),
-      is_anonymous_text_(IsPhysicalTextFragmentAnonymousText(layout_object)) {
+      shape_result_(shape_result) {
   DCHECK(shape_result_ || IsFlowControl()) << ToString();
+  line_orientation_ = static_cast<unsigned>(line_orientation);
+  is_anonymous_text_ = IsPhysicalTextFragmentAnonymousText(layout_object);
+
   self_ink_overflow_ = ComputeSelfInkOverflow();
 }
 
@@ -79,13 +88,13 @@ NGPhysicalTextFragment::NGPhysicalTextFragment(NGTextFragmentBuilder* builder)
       text_(builder->text_),
       start_offset_(builder->start_offset_),
       end_offset_(builder->end_offset_),
-      shape_result_(std::move(builder->shape_result_)),
-      line_orientation_(
-          static_cast<unsigned>(ToLineOrientation(builder->GetWritingMode()))),
-      end_effect_(static_cast<unsigned>(builder->end_effect_)),
-      is_anonymous_text_(
-          IsPhysicalTextFragmentAnonymousText(builder->layout_object_)) {
+      shape_result_(std::move(builder->shape_result_)) {
   DCHECK(shape_result_ || IsFlowControl()) << ToString();
+  line_orientation_ =
+      static_cast<unsigned>(ToLineOrientation(builder->GetWritingMode()));
+  is_anonymous_text_ =
+      IsPhysicalTextFragmentAnonymousText(builder->layout_object_);
+
   self_ink_overflow_ = ComputeSelfInkOverflow();
 }
 
@@ -247,8 +256,7 @@ scoped_refptr<const NGPhysicalFragment> NGPhysicalTextFragment::TrimText(
       TextType(), text_, new_start_offset, new_end_offset,
       IsHorizontal() ? NGPhysicalSize{new_inline_size, size_.height}
                      : NGPhysicalSize{size_.width, new_inline_size},
-      LineOrientation(), EndEffect(),
-      ShapeResultView::Create(new_shape_result.get())));
+      LineOrientation(), ShapeResultView::Create(new_shape_result.get())));
 }
 
 unsigned NGPhysicalTextFragment::TextOffsetForPoint(
@@ -299,7 +307,7 @@ UBiDiLevel NGPhysicalTextFragment::BidiLevel() const {
 TextDirection NGPhysicalTextFragment::ResolvedDirection() const {
   if (TextShapeResult())
     return TextShapeResult()->Direction();
-  return NGPhysicalFragment::ResolvedDirection();
+  return DirectionFromLevel(BidiLevel());
 }
 
 }  // namespace blink

third_party/blink/renderer/core/layout/ng/inline/ng_physical_text_fragment.h

@@ -104,10 +104,6 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
   // properties, in local coordinates.
   NGPhysicalOffsetRect SelfInkOverflow() const { return self_ink_overflow_; }
 
-  NGTextEndEffect EndEffect() const {
-    return static_cast<NGTextEndEffect>(end_effect_);
-  }
-
   // Create a new fragment that has part of the text of this fragment.
   // All other properties are the same as this fragment.
   scoped_refptr<const NGPhysicalFragment> TrimText(unsigned start_offset,
@@ -127,8 +123,8 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
   // Returns the text offset in the fragment placed closest to the given point.
   unsigned TextOffsetForPoint(const NGPhysicalOffset&) const;
 
-  UBiDiLevel BidiLevel() const override;
-  TextDirection ResolvedDirection() const override;
+  UBiDiLevel BidiLevel() const;
+  TextDirection ResolvedDirection() const;
 
   // Compute line-relative coordinates for given offsets, this is not
   // flow-relative:
@@ -148,7 +144,6 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
                          unsigned end_offset,
                          NGPhysicalSize size,
                          NGLineOrientation line_orientation,
-                         NGTextEndEffect end_effect,
                          scoped_refptr<const ShapeResultView> shape_result);
 
   LayoutUnit InlinePositionForOffset(unsigned offset,
@@ -168,10 +163,6 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
   const unsigned end_offset_;
   NGPhysicalOffsetRect self_ink_overflow_;
   const scoped_refptr<const ShapeResultView> shape_result_;
-
-  const unsigned line_orientation_ : 2;  // NGLineOrientation
-  const unsigned end_effect_ : 1;        // NGTextEndEffect
-  const unsigned is_anonymous_text_ : 1;
 };
 
 DEFINE_TYPE_CASTS(NGPhysicalTextFragment,

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

@@ -17,6 +17,19 @@
 
 namespace blink {
 
+namespace {
+
+struct SameSizeAsNGPhysicalBoxFragment : NGPhysicalContainerFragment {
+  NGBaselineList baselines;
+  NGPhysicalBoxStrut box_struts[2];
+};
+
+static_assert(sizeof(NGPhysicalBoxFragment) ==
+                  sizeof(SameSizeAsNGPhysicalBoxFragment),
+              "NGPhysicalBoxFragment should stay small");
+
+}  // namespace
+
 scoped_refptr<const NGPhysicalBoxFragment> NGPhysicalBoxFragment::Create(
     NGBoxFragmentBuilder* builder,
     WritingMode block_or_line_writing_mode) {

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

@@ -82,7 +82,7 @@ class CORE_EXPORT NGPhysicalBoxFragment final
                            const LayoutPoint& additional_offset,
                            NGOutlineType include_block_overflows) const;
 
-  UBiDiLevel BidiLevel() const override;
+  UBiDiLevel BidiLevel() const;
 
   scoped_refptr<const NGPhysicalFragment> CloneWithoutOffset() const;
 

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

@@ -14,6 +14,19 @@
 
 namespace blink {
 
+namespace {
+
+struct SameSizeAsNGPhysicalContainerFragment : NGPhysicalFragment {
+  wtf_size_t size;
+  void* pointer;
+};
+
+static_assert(sizeof(NGPhysicalContainerFragment) ==
+                  sizeof(SameSizeAsNGPhysicalContainerFragment),
+              "NGPhysicalContainerFragment should stay small");
+
+}  // namespace
+
 NGPhysicalContainerFragment::NGPhysicalContainerFragment(
     NGContainerFragmentBuilder* builder,
     WritingMode block_or_line_writing_mode,

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

@@ -21,6 +21,17 @@
 namespace blink {
 namespace {
 
+struct SameSizeAsNGPhysicalFragment
+    : RefCounted<const NGPhysicalFragment, NGPhysicalFragmentTraits> {
+  void* pointers[3];
+  NGPhysicalSize size;
+  unsigned flags;
+};
+
+static_assert(sizeof(NGPhysicalFragment) ==
+                  sizeof(SameSizeAsNGPhysicalFragment),
+              "NGPhysicalFragment should stay small");
+
 bool AppendFragmentOffsetAndSize(
     const NGPhysicalFragment* fragment,
     base::Optional<NGPhysicalOffset> fragment_offset,
@@ -434,15 +445,33 @@ TouchAction NGPhysicalFragment::EffectiveWhitelistedTouchAction() const {
 }
 
 UBiDiLevel NGPhysicalFragment::BidiLevel() const {
+  switch (Type()) {
+    case kFragmentText:
+      return ToNGPhysicalTextFragment(*this).BidiLevel();
+    case kFragmentBox:
+    case kFragmentRenderedLegend:
+      return ToNGPhysicalBoxFragment(*this).BidiLevel();
+    case kFragmentLineBox:
+      break;
+  }
   NOTREACHED();
   return 0;
 }
 
 TextDirection NGPhysicalFragment::ResolvedDirection() const {
-  DCHECK(IsInline());
-  DCHECK(IsText() || IsAtomicInline());
-  // TODO(xiaochengh): Store direction in |base_direction_| flag.
-  return DirectionFromLevel(BidiLevel());
+  switch (Type()) {
+    case kFragmentText:
+      return ToNGPhysicalTextFragment(*this).ResolvedDirection();
+    case kFragmentBox:
+    case kFragmentRenderedLegend:
+      DCHECK(IsInline() && IsAtomicInline());
+      // TODO(xiaochengh): Store direction in |base_direction_| flag.
+      return DirectionFromLevel(BidiLevel());
+    case kFragmentLineBox:
+      break;
+  }
+  NOTREACHED();
+  return TextDirection::kLtr;
 }
 
 String NGPhysicalFragment::ToString() const {

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

@@ -199,11 +199,11 @@ class CORE_EXPORT NGPhysicalFragment
   TouchAction EffectiveWhitelistedTouchAction() const;
 
   // Returns the bidi level of a text or atomic inline fragment.
-  virtual UBiDiLevel BidiLevel() const;
+  UBiDiLevel BidiLevel() const;
 
   // Returns the resolved direction of a text or atomic inline fragment. Not to
   // be confused with the CSS 'direction' property.
-  virtual TextDirection ResolvedDirection() const;
+  TextDirection ResolvedDirection() const;
 
   String ToString() const;
 
@@ -256,12 +256,20 @@ class CORE_EXPORT NGPhysicalFragment
   unsigned is_old_layout_root_ : 1;
   unsigned border_edge_ : 4;  // NGBorderEdges::Physical
   const unsigned style_variant_ : 2;  // NGStyleVariant
-  unsigned base_direction_ : 1;  // TextDirection, for NGPhysicalLineBoxFragment
+
+  // The following bitfield is only to be used by NGPhysicalLineBoxFragment
+  // (it's defined here to save memory, since that class has no bitfields).
+  unsigned base_direction_ : 1;  // TextDirection
 
   // The following bitfield is only to be used by NGPhysicalBoxFragment (it's
   // defined here to save memory, since that class has no bitfields).
   unsigned children_inline_ : 1;
 
+  // The following bitfield is only to be used by NGPhysicalTextFragment (it's
+  // defined here to save memory, since that class has no bitfields).
+  unsigned line_orientation_ : 2;  // NGLineOrientation
+  unsigned is_anonymous_text_ : 1;
+
  private:
   friend struct NGPhysicalFragmentTraits;
   void Destroy() const;