[LayoutNG] Reduces the size of NGPhysical{Box|Text}Fragment

This patch reduces the size of:
* NGPhysicalBoxFragment by a pointer, by removing |style_|
  from NGPhysicalFragment. This field is used only for line
  box and for ellipsis, and thus it is moved to each
  subclasses.
* NGPhysicalTextFragment by 16 bytes, by moving
  |self_ink_overflow_| and |style_| to RareData. Quick
  investigation shows that |self_ink_overflow_| is different
  from |LocalRect()| in 10-20% of the time (on Linux,
  google.com and a few other sites.)

Change-Id: I225edd42d6d9488611ffe2fa7ef9b11b7e9da4a1
Bug: 635619, 636993
Reviewed-on: https://chromium-review.googlesource.com/c/1331102Reviewed-by: Aleks Totic <atotic@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607444}

third_party/blink/renderer/core/layout/ng/geometry/ng_physical_offset_rect.cc

@@ -15,6 +15,11 @@ bool NGPhysicalOffsetRect::operator==(const NGPhysicalOffsetRect& other) const {
   return other.offset == offset && other.size == size;
 }
 
+bool NGPhysicalOffsetRect::Contains(const NGPhysicalOffsetRect& other) const {
+  return offset.left <= other.offset.left && offset.top <= other.offset.top &&
+         Right() >= other.Right() && Bottom() >= other.Bottom();
+}
+
 NGPhysicalOffsetRect NGPhysicalOffsetRect::operator+(
     const NGPhysicalOffset& offset) const {
   return {this->offset + offset, size};

third_party/blink/renderer/core/layout/ng/geometry/ng_physical_offset_rect.h

@@ -34,6 +34,8 @@ struct CORE_EXPORT NGPhysicalOffsetRect {
 
   bool operator==(const NGPhysicalOffsetRect& other) const;
 
+  bool Contains(const NGPhysicalOffsetRect& other) const;
+
   NGPhysicalOffsetRect operator+(const NGPhysicalOffset&) const;
 
   void Unite(const NGPhysicalOffsetRect&);

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

@@ -14,6 +14,7 @@ namespace blink {
 namespace {
 
 struct SameSizeAsNGPhysicalLineBoxFragment : NGPhysicalContainerFragment {
+  void* pointer;
   NGLineHeightMetrics metrics;
 };
 
@@ -46,6 +47,7 @@ NGPhysicalLineBoxFragment::NGPhysicalLineBoxFragment(
                                   kFragmentLineBox,
                                   0),
       metrics_(builder->metrics_) {
+  style_ = std::move(builder->style_);
   base_direction_ = static_cast<unsigned>(builder->base_direction_);
 }
 

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

@@ -29,6 +29,7 @@ class CORE_EXPORT NGPhysicalLineBoxFragment final
     return ChildLinkList(num_children_, &children_[0]);
   }
 
+  const ComputedStyle& Style() const { return *style_; }
   const NGLineHeightMetrics& Metrics() const { return metrics_; }
 
   // The base direction of this line. Also known as the paragraph direction.
@@ -66,6 +67,7 @@ class CORE_EXPORT NGPhysicalLineBoxFragment final
  private:
   NGPhysicalLineBoxFragment(NGLineBoxFragmentBuilder* builder);
 
+  scoped_refptr<const ComputedStyle> style_;
   NGLineHeightMetrics metrics_;
   NGLinkStorage children_[];
 };

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

@@ -19,8 +19,7 @@ namespace blink {
 namespace {
 
 struct SameSizeAsNGPhysicalTextFragment : NGPhysicalFragment {
-  void* pointers[2];
-  NGPhysicalOffsetRect rect;
+  void* pointers[3];
   unsigned offsets[2];
 };
 
@@ -56,31 +55,31 @@ NGLineOrientation ToLineOrientation(WritingMode writing_mode) {
 }  // anonymous namespace
 
 NGPhysicalTextFragment::NGPhysicalTextFragment(
-    LayoutObject* layout_object,
-    const ComputedStyle& style,
-    NGStyleVariant style_variant,
-    NGTextType text_type,
-    const String& text,
+    const NGPhysicalTextFragment& source,
     unsigned start_offset,
     unsigned end_offset,
-    NGPhysicalSize size,
-    NGLineOrientation line_orientation,
     scoped_refptr<const ShapeResultView> shape_result)
-    : NGPhysicalFragment(layout_object,
-                         style,
-                         style_variant,
-                         size,
+    : NGPhysicalFragment(source.GetLayoutObject(),
+                         source.StyleVariant(),
+                         source.IsHorizontal()
+                             ? NGPhysicalSize{shape_result->SnappedWidth(),
+                                              source.Size().height}
+                             : NGPhysicalSize{source.Size().width,
+                                              shape_result->SnappedWidth()},
                          kFragmentText,
-                         text_type),
-      text_(text),
+                         source.TextType()),
+      text_(source.text_),
       start_offset_(start_offset),
       end_offset_(end_offset),
       shape_result_(shape_result) {
+  DCHECK_GE(start_offset_, source.StartOffset());
+  DCHECK_LE(end_offset_, source.EndOffset());
   DCHECK(shape_result_ || IsFlowControl()) << ToString();
-  line_orientation_ = static_cast<unsigned>(line_orientation);
-  is_anonymous_text_ = IsPhysicalTextFragmentAnonymousText(layout_object);
+  DCHECK(!source.rare_data_ || !source.rare_data_->style_);
+  line_orientation_ = source.line_orientation_;
+  is_anonymous_text_ = source.is_anonymous_text_;
 
-  self_ink_overflow_ = ComputeSelfInkOverflow();
+  UpdateSelfInkOverflow();
 }
 
 NGPhysicalTextFragment::NGPhysicalTextFragment(NGTextFragmentBuilder* builder)
@@ -95,7 +94,29 @@ NGPhysicalTextFragment::NGPhysicalTextFragment(NGTextFragmentBuilder* builder)
   is_anonymous_text_ =
       IsPhysicalTextFragmentAnonymousText(builder->layout_object_);
 
-  self_ink_overflow_ = ComputeSelfInkOverflow();
+  if (UNLIKELY(StyleVariant() == NGStyleVariant::kEllipsis))
+    EnsureRareData()->style_ = std::move(builder->style_);
+
+  UpdateSelfInkOverflow();
+}
+
+NGPhysicalTextFragment::RareData* NGPhysicalTextFragment::EnsureRareData() {
+  if (!rare_data_)
+    rare_data_ = std::make_unique<RareData>();
+  return rare_data_.get();
+}
+
+const ComputedStyle& NGPhysicalTextFragment::Style() const {
+  switch (StyleVariant()) {
+    case NGStyleVariant::kStandard:
+    case NGStyleVariant::kFirstLine:
+      return NGPhysicalFragment::Style();
+    case NGStyleVariant::kEllipsis:
+      DCHECK(rare_data_ && rare_data_->style_);
+      return *rare_data_->style_;
+  }
+  NOTREACHED();
+  return NGPhysicalFragment::Style();
 }
 
 // Convert logical cooridnate to local physical coordinate.
@@ -185,9 +206,20 @@ NGPhysicalOffsetRect NGPhysicalTextFragment::LocalRect(
   return {};
 }
 
-NGPhysicalOffsetRect NGPhysicalTextFragment::ComputeSelfInkOverflow() const {
-  if (UNLIKELY(!shape_result_))
-    return LocalRect();
+NGPhysicalOffsetRect NGPhysicalTextFragment::SelfInkOverflow() const {
+  return UNLIKELY(rare_data_) ? rare_data_->self_ink_overflow_ : LocalRect();
+}
+
+void NGPhysicalTextFragment::ClearSelfInkOverflow() {
+  if (UNLIKELY(rare_data_))
+    rare_data_->self_ink_overflow_ = LocalRect();
+}
+
+void NGPhysicalTextFragment::UpdateSelfInkOverflow() {
+  if (UNLIKELY(!shape_result_)) {
+    ClearSelfInkOverflow();
+    return;
+  }
 
   // Glyph bounds is in logical coordinate, origin at the alphabetic baseline.
   LayoutRect ink_overflow = EnclosingLayoutRect(shape_result_->Bounds());
@@ -234,8 +266,13 @@ NGPhysicalOffsetRect NGPhysicalTextFragment::ComputeSelfInkOverflow() const {
   // Uniting the frame rect ensures that non-ink spaces such side bearings, or
   // even space characters, are included in the visual rect for decorations.
   NGPhysicalOffsetRect local_ink_overflow = ConvertToLocal(ink_overflow);
-  local_ink_overflow.Unite(LocalRect());
-  return local_ink_overflow;
+  NGPhysicalOffsetRect local_rect = LocalRect();
+  if (local_rect.Contains(local_ink_overflow)) {
+    ClearSelfInkOverflow();
+    return;
+  }
+  local_ink_overflow.Unite(local_rect);
+  EnsureRareData()->self_ink_overflow_ = local_ink_overflow;
 }
 
 scoped_refptr<const NGPhysicalFragment> NGPhysicalTextFragment::TrimText(
@@ -250,13 +287,9 @@ scoped_refptr<const NGPhysicalFragment> NGPhysicalTextFragment::TrimText(
   scoped_refptr<ShapeResult> new_shape_result =
       shape_result_->CreateShapeResult()->SubRange(new_start_offset,
                                                    new_end_offset);
-  LayoutUnit new_inline_size = new_shape_result->SnappedWidth();
   return base::AdoptRef(new NGPhysicalTextFragment(
-      layout_object_, Style(), static_cast<NGStyleVariant>(style_variant_),
-      TextType(), text_, new_start_offset, new_end_offset,
-      IsHorizontal() ? NGPhysicalSize{new_inline_size, size_.height}
-                     : NGPhysicalSize{size_.width, new_inline_size},
-      LineOrientation(), ShapeResultView::Create(new_shape_result.get())));
+      *this, new_start_offset, new_end_offset,
+      ShapeResultView::Create(new_shape_result.get())));
 }
 
 unsigned NGPhysicalTextFragment::TextOffsetForPoint(

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

@@ -72,6 +72,8 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
     return IsLineBreak() || TextType() == kFlowControl;
   }
 
+  const ComputedStyle& Style() const;
+
   unsigned Length() const { return end_offset_ - start_offset_; }
   StringView Text() const { return StringView(text_, start_offset_, Length()); }
   const String& TextContent() const { return text_; }
@@ -102,7 +104,7 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
 
   // The visual bounding box that includes glpyh bounding box and CSS
   // properties, in local coordinates.
-  NGPhysicalOffsetRect SelfInkOverflow() const { return self_ink_overflow_; }
+  NGPhysicalOffsetRect SelfInkOverflow() const;
 
   // Create a new fragment that has part of the text of this fragment.
   // All other properties are the same as this fragment.
@@ -135,24 +137,25 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
 
  private:
   // For use by TrimText only
-  NGPhysicalTextFragment(LayoutObject* layout_object,
-                         const ComputedStyle& style,
-                         NGStyleVariant style_variant,
-                         NGTextType text_type,
-                         const String& text,
+  NGPhysicalTextFragment(const NGPhysicalTextFragment& source,
                          unsigned start_offset,
                          unsigned end_offset,
-                         NGPhysicalSize size,
-                         NGLineOrientation line_orientation,
                          scoped_refptr<const ShapeResultView> shape_result);
 
+  struct RareData {
+    NGPhysicalOffsetRect self_ink_overflow_;
+    scoped_refptr<const ComputedStyle> style_;  // Used only for ellipsis.
+  };
+  RareData* EnsureRareData();
+
   LayoutUnit InlinePositionForOffset(unsigned offset,
                                      LayoutUnit (*round)(float),
                                      AdjustMidCluster) const;
 
   NGPhysicalOffsetRect ConvertToLocal(const LayoutRect&) const;
 
-  NGPhysicalOffsetRect ComputeSelfInkOverflow() const;
+  void UpdateSelfInkOverflow();
+  void ClearSelfInkOverflow();
 
   // The text of NGInlineNode; i.e., of a parent block. The text for this
   // fragment is a substring(start_offset_, end_offset_) of this string.
@@ -161,8 +164,9 @@ class CORE_EXPORT NGPhysicalTextFragment final : public NGPhysicalFragment {
   // Start and end offset of the parent block text.
   const unsigned start_offset_;
   const unsigned end_offset_;
-  NGPhysicalOffsetRect self_ink_overflow_;
   const scoped_refptr<const ShapeResultView> shape_result_;
+
+  std::unique_ptr<RareData> rare_data_;
 };
 
 DEFINE_TYPE_CASTS(NGPhysicalTextFragment,

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

@@ -23,7 +23,7 @@ namespace {
 
 struct SameSizeAsNGPhysicalFragment
     : RefCounted<const NGPhysicalFragment, NGPhysicalFragmentTraits> {
-  void* pointers[3];
+  void* pointers[2];
   NGPhysicalSize size;
   unsigned flags;
 };
@@ -249,7 +249,6 @@ NGPhysicalFragment::NGPhysicalFragment(NGFragmentBuilder* builder,
                                        NGFragmentType type,
                                        unsigned sub_type)
     : layout_object_(builder->layout_object_),
-      style_(std::move(builder->style_)),
       size_(ToNGPhysicalSize(builder->size_, builder->GetWritingMode())),
       break_token_(std::move(builder->break_token_)),
       type_(type),
@@ -259,14 +258,12 @@ NGPhysicalFragment::NGPhysicalFragment(NGFragmentBuilder* builder,
       style_variant_((unsigned)builder->style_variant_) {}
 
 NGPhysicalFragment::NGPhysicalFragment(LayoutObject* layout_object,
-                                       const ComputedStyle& style,
                                        NGStyleVariant style_variant,
                                        NGPhysicalSize size,
                                        NGFragmentType type,
                                        unsigned sub_type,
                                        scoped_refptr<NGBreakToken> break_token)
     : layout_object_(layout_object),
-      style_(&style),
       size_(size),
       break_token_(std::move(break_token)),
       type_(type),
@@ -298,21 +295,20 @@ void NGPhysicalFragment::Destroy() const {
 }
 
 const ComputedStyle& NGPhysicalFragment::Style() const {
-  DCHECK(style_);
-  // TODO(kojii): Returning |style_| locks the style at the layout time, and
-  // will not be updated when its base style is updated later. Line styles and
-  // ellipsis styles have this problem.
-  if (!GetLayoutObject())
-    return *style_;
+  if (Type() == kFragmentLineBox)
+    return ToNGPhysicalLineBoxFragment(this)->Style();
   switch (StyleVariant()) {
     case NGStyleVariant::kStandard:
+      DCHECK(GetLayoutObject());
       return *GetLayoutObject()->Style();
     case NGStyleVariant::kFirstLine:
+      DCHECK(GetLayoutObject());
       return *GetLayoutObject()->FirstLineStyle();
     case NGStyleVariant::kEllipsis:
-      return *style_;
+      return ToNGPhysicalTextFragment(this)->Style();
   }
-  return *style_;
+  NOTREACHED();
+  return *GetLayoutObject()->Style();
 }
 
 Node* NGPhysicalFragment::GetNode() const {

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

@@ -236,7 +236,6 @@ class CORE_EXPORT NGPhysicalFragment
                      unsigned sub_type);
 
   NGPhysicalFragment(LayoutObject* layout_object,
-                     const ComputedStyle& style,
                      NGStyleVariant,
                      NGPhysicalSize size,
                      NGFragmentType type,
@@ -246,7 +245,6 @@ class CORE_EXPORT NGPhysicalFragment
   const Vector<NGInlineItem>& InlineItemsOfContainingBlock() const;
 
   LayoutObject* const layout_object_;
-  scoped_refptr<const ComputedStyle> style_;
   const NGPhysicalSize size_;
   scoped_refptr<NGBreakToken> break_token_;