<ruby>: Introduce |text-align: -internal-space-around|

This CL adds |-internal-space-around| keyword to |text-align| CSS
property. It is used for the default value of ruby annotation boxes
and ruby base boxes.

We assumed |start|, the initial value of text-align, in ComputedStyle
had a special effect for ruby annotation and ruby base, and we made a
variant of kJustify internally.  The code was complicated, and
introducing |-internal-space-around| simplifies the code.

This CL has a small behavior change:
 - If text-align:start is specified to <rt>, we ignored it before this
   CL and applied the 'space-around' behavior.
   After this CL, we apply text-align:start behavior in that case.

* LayoutRubyRun.cc
  ComputedStyle for LayoutRubyBase was sometimes overwritten by
  LayoutObject::PropagateStyleToAnonymousChildren(), and the TextAlign
  value was reset to kStart. Uses UpdateAnonymousChildStyle() to keep
  the expected TextAlign value.

* insert-paragraph-into-table-expected.txt
  |style="text-align: -internal-space-around;"|, which is unable to
  parse, appears.  This will be fixed when we implement ruby-align CSS
  property.

Bug: 1069817
Change-Id: Iecc1e999d11b58dd4d950f3579310546f5db7585
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2217673
Commit-Queue: Kent Tamura <tkent@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773079}

third_party/blink/renderer/core/css/css_properties.json5

@@ -3518,7 +3518,7 @@
       field_template: "keyword",
       keywords: [
         "left", "right", "center", "justify", "-webkit-left", "-webkit-right",
-        "-webkit-center", "start", "end"
+        "-webkit-center", "start", "end", "-internal-space-around"
       ],
       typedom_types: ["Keyword"],
       default_value: "start",
@@ -3531,7 +3531,8 @@
       inherited: true,
       field_group: "*",
       field_template: "keyword",
-      keywords: ["auto", "start", "end", "left", "right", "center", "justify"],
+      keywords: ["auto", "start", "end", "left", "right", "center", "justify",
+                 "-internal-space-around"],
       default_value: "auto",
       typedom_types: ["Keyword"]
     },

third_party/blink/renderer/core/css/css_value_keywords.json5

@@ -281,6 +281,7 @@
     "-webkit-center",
     "-webkit-match-parent",
     "-internal-center",
+    "-internal-space-around",
     //
     // text-justify
     //

third_party/blink/renderer/core/css/parser/css_parser_fast_paths.cc

@@ -735,13 +735,14 @@ bool CSSParserFastPaths::IsValidKeywordPropertyAndValue(
       return value_id == CSSValueID::kAuto || value_id == CSSValueID::kFixed;
     case CSSPropertyID::kTextAlign:
       return (value_id >= CSSValueID::kWebkitAuto &&
-              value_id <= CSSValueID::kInternalCenter) ||
+              value_id <= CSSValueID::kInternalSpaceAround) ||
              value_id == CSSValueID::kStart || value_id == CSSValueID::kEnd;
     case CSSPropertyID::kTextAlignLast:
       return (value_id >= CSSValueID::kLeft &&
               value_id <= CSSValueID::kJustify) ||
              value_id == CSSValueID::kStart || value_id == CSSValueID::kEnd ||
-             value_id == CSSValueID::kAuto;
+             value_id == CSSValueID::kAuto ||
+             value_id == CSSValueID::kInternalSpaceAround;
     case CSSPropertyID::kTextAnchor:
       return value_id == CSSValueID::kStart ||
              value_id == CSSValueID::kMiddle || value_id == CSSValueID::kEnd;

third_party/blink/renderer/core/editing/editing_style.cc

@@ -477,6 +477,8 @@ static CSSValueID TextAlignResolvingStartAndEnd(CSSValueID text_align,
       return CSSValueID::kCenter;
     case CSSValueID::kJustify:
       return CSSValueID::kJustify;
+    case CSSValueID::kInternalSpaceAround:
+      return CSSValueID::kInternalSpaceAround;
     case CSSValueID::kLeft:
     case CSSValueID::kWebkitLeft:
       return CSSValueID::kLeft;

third_party/blink/renderer/core/html/resources/html.css

@@ -1090,7 +1090,7 @@ rt {
 ruby > rt {
     display: block;
     font-size: 50%;
-    text-align: start;
+    text-align: -internal-space-around;
 }
 
 rp {

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

@@ -402,11 +402,6 @@ class CORE_EXPORT LayoutBlock : public LayoutBox {
   MinMaxSizes PreferredLogicalWidths() const override;
 
  protected:
-  virtual void AdjustInlineDirectionLineBounds(
-      unsigned /* expansionOpportunityCount */,
-      LayoutUnit& /* logicalLeft */,
-      LayoutUnit& /* logicalWidth */) const {}
-
   MinMaxSizes ComputeIntrinsicLogicalWidths() const override;
   void ComputeChildPreferredLogicalWidths(
       LayoutObject& child,

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

@@ -849,8 +849,6 @@ class CORE_EXPORT LayoutBlockFlow : public LayoutBlock {
     }
   }
 
-  virtual ETextAlign TextAlignmentForLine(bool ends_with_soft_break) const;
-
  private:
   LayoutUnit CollapsedMarginBefore() const final {
     return MaxPositiveMarginBefore() - MaxNegativeMarginBefore();

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

@@ -363,11 +363,6 @@ RootInlineBox* LayoutBlockFlow::ConstructLine(BidiRunList<BidiRun>& bidi_runs,
   return LastRootBox();
 }
 
-ETextAlign LayoutBlockFlow::TextAlignmentForLine(
-    bool ends_with_soft_break) const {
-  return StyleRef().GetTextAlign(!ends_with_soft_break);
-}
-
 static bool TextAlignmentNeedsTrailingSpace(ETextAlign text_align,
                                             const ComputedStyle& style) {
   switch (text_align) {
@@ -379,6 +374,7 @@ static bool TextAlignmentNeedsTrailingSpace(ETextAlign text_align,
     case ETextAlign::kCenter:
     case ETextAlign::kWebkitCenter:
     case ETextAlign::kJustify:
+    case ETextAlign::kInternalSpaceAround:
       return style.CollapseWhiteSpace();
     case ETextAlign::kStart:
       return style.CollapseWhiteSpace() && !style.IsLeftToRightDirection();
@@ -691,9 +687,30 @@ void LayoutBlockFlow::UpdateLogicalWidthForAlignment(
           StyleRef().IsLeftToRightDirection(), trailing_space_run, logical_left,
           total_logical_width, available_logical_width);
       break;
+
+    case ETextAlign::kInternalSpaceAround: {
+      int max_preferred_logical_width =
+          PreferredLogicalWidths().max_size.ToInt();
+      if (max_preferred_logical_width < available_logical_width) {
+        unsigned capped_count =
+            static_cast<unsigned>(LayoutUnit::Max().Floor());
+        capped_count = std::min(expansion_opportunity_count, capped_count);
+
+        // Inset the line by half the inter-ideograph expansion amount.
+        LayoutUnit inset =
+            (available_logical_width - max_preferred_logical_width) /
+            (capped_count + 1);
+        // For <rt>,  inset it by no more than a full-width ruby character on
+        // each side.
+        if (IsRubyText() && capped_count > 0)
+          inset = std::min(LayoutUnit(2 * StyleRef().FontSize()), inset);
+
+        logical_left += inset / 2;
+        available_logical_width -= inset;
+      }
+      FALLTHROUGH;
+    }
     case ETextAlign::kJustify:
-      AdjustInlineDirectionLineBounds(expansion_opportunity_count, logical_left,
-                                      available_logical_width);
       if (expansion_opportunity_count) {
         if (trailing_space_run) {
           total_logical_width -= trailing_space_run->box_->LogicalWidth();
@@ -821,8 +838,9 @@ BidiRun* LayoutBlockFlow::ComputeInlineDirectionPositionsForSegment(
     }
     if (r->line_layout_item_.IsText()) {
       LineLayoutText rt(r->line_layout_item_);
-      if (text_align == ETextAlign::kJustify && r != trailing_space_run &&
-          text_justify != TextJustify::kNone) {
+      if ((text_align == ETextAlign::kJustify ||
+           text_align == ETextAlign::kInternalSpaceAround) &&
+          r != trailing_space_run && text_justify != TextJustify::kNone) {
         if (!is_after_expansion)
           ToInlineTextBox(r->box_)->SetCanHaveLeadingExpansion(true);
         expansions.AddRunWithExpansions(*r, is_after_expansion, text_justify);
@@ -1166,9 +1184,9 @@ void LayoutBlockFlow::LayoutRunsAndFloatsInRange(
             BidiStatus(direction, IsOverride(style_to_use.GetUnicodeBidi())));
       }
 
-      ETextAlign text_align = TextAlignmentForLine(
-          !end_of_line.AtEnd() &&
-          !layout_state.GetLineInfo().PreviousLineBrokeCleanly());
+      ETextAlign text_align = StyleRef().GetTextAlign(
+          end_of_line.AtEnd() ||
+          layout_state.GetLineInfo().PreviousLineBrokeCleanly());
       layout_state.GetLineInfo().SetTextAlign(text_align);
       resolver.SetNeedsTrailingSpace(
           TextAlignmentNeedsTrailingSpace(text_align, style_to_use));

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

@@ -1270,6 +1270,7 @@ LayoutRect LayoutBoxModelObject::LocalCaretRectForEmptyElement(
       alignment = kAlignRight;
       break;
     case ETextAlign::kJustify:
+    case ETextAlign::kInternalSpaceAround:
     case ETextAlign::kStart:
       if (!current_style.IsLeftToRightDirection())
         alignment = kAlignRight;

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

@@ -154,29 +154,4 @@ void LayoutRubyBase::MoveBlockChildren(LayoutRubyBase* to_base,
   }
 }
 
-ETextAlign LayoutRubyBase::TextAlignmentForLine(
-    bool /* endsWithSoftBreak */) const {
-  return ETextAlign::kJustify;
-}
-
-void LayoutRubyBase::AdjustInlineDirectionLineBounds(
-    unsigned expansion_opportunity_count,
-    LayoutUnit& logical_left,
-    LayoutUnit& logical_width) const {
-  int max_preferred_logical_width = PreferredLogicalWidths().max_size.ToInt();
-  if (max_preferred_logical_width >= logical_width)
-    return;
-
-  unsigned max_count = static_cast<unsigned>(LayoutUnit::Max().Floor());
-  if (expansion_opportunity_count > max_count)
-    expansion_opportunity_count = max_count;
-
-  // Inset the ruby base by half the inter-ideograph expansion amount.
-  LayoutUnit inset = (logical_width - max_preferred_logical_width) /
-                     (expansion_opportunity_count + 1);
-
-  logical_left += inset / 2;
-  logical_width -= inset;
-}
-
 }  // namespace blink

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

@@ -58,12 +58,6 @@ class LayoutRubyBase : public LayoutBlockFlow {
   // constructor.
   explicit LayoutRubyBase(Element*);
 
-  ETextAlign TextAlignmentForLine(bool ends_with_soft_break) const override;
-  void AdjustInlineDirectionLineBounds(
-      unsigned expansion_opportunity_count,
-      LayoutUnit& logical_left,
-      LayoutUnit& logical_width) const override;
-
   void MoveChildren(LayoutRubyBase* to_base,
                     LayoutObject* before_child = nullptr);
   void MoveInlineChildren(LayoutRubyBase* to_base,

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

@@ -188,11 +188,19 @@ LayoutRubyBase* LayoutRubyRun::CreateRubyBase() const {
   scoped_refptr<ComputedStyle> new_style =
       ComputedStyle::CreateAnonymousStyleWithDisplay(StyleRef(),
                                                      EDisplay::kBlock);
-  new_style->SetTextAlign(ETextAlign::kCenter);  // FIXME: use WEBKIT_CENTER?
+  UpdateAnonymousChildStyle(layout_object, *new_style);
   layout_object->SetStyle(std::move(new_style));
   return layout_object;
 }
 
+void LayoutRubyRun::UpdateAnonymousChildStyle(
+    const LayoutObject* child,
+    ComputedStyle& child_style) const {
+  DCHECK(child->IsRubyBase()) << child;
+  child_style.SetDisplay(EDisplay::kBlock);
+  child_style.SetTextAlign(ETextAlign::kInternalSpaceAround);
+}
+
 LayoutRubyRun* LayoutRubyRun::StaticCreateRubyRun(
     const LayoutObject* parent_ruby,
     const LayoutBlock& containing_block) {

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

@@ -91,6 +91,8 @@ class LayoutRubyRun : public LayoutBlockFlow {
   }
   bool CreatesAnonymousWrapper() const override { return true; }
   void RemoveLeftoverAnonymousBlock(LayoutBlock*) override {}
+  void UpdateAnonymousChildStyle(const LayoutObject* child,
+                                 ComputedStyle& child_style) const override;
 
   friend class LayoutNGMixin<LayoutRubyRun>;
 };

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

@@ -42,41 +42,4 @@ bool LayoutRubyText::IsChildAllowed(LayoutObject* child,
   return child->IsInline();
 }
 
-ETextAlign LayoutRubyText::TextAlignmentForLine(
-    bool ends_with_soft_break) const {
-  ETextAlign text_align = StyleRef().GetTextAlign();
-  // FIXME: This check is bogus since user can set the initial value.
-  if (text_align != ComputedStyleInitialValues::InitialTextAlign())
-    return LayoutBlockFlow::TextAlignmentForLine(ends_with_soft_break);
-
-  // The default behavior is to allow ruby text to expand if it is shorter than
-  // the ruby base.
-  return ETextAlign::kJustify;
-}
-
-void LayoutRubyText::AdjustInlineDirectionLineBounds(
-    unsigned expansion_opportunity_count,
-    LayoutUnit& logical_left,
-    LayoutUnit& logical_width) const {
-  ETextAlign text_align = StyleRef().GetTextAlign();
-  // FIXME: This check is bogus since user can set the initial value.
-  if (text_align != ComputedStyleInitialValues::InitialTextAlign())
-    return LayoutBlockFlow::AdjustInlineDirectionLineBounds(
-        expansion_opportunity_count, logical_left, logical_width);
-
-  int max_preferred_logical_width = PreferredLogicalWidths().max_size.ToInt();
-  if (max_preferred_logical_width >= logical_width)
-    return;
-
-  // Inset the ruby text by half the inter-ideograph expansion amount, but no
-  // more than a full-width ruby character on each side.
-  LayoutUnit inset = (logical_width - max_preferred_logical_width) /
-                     (expansion_opportunity_count + 1);
-  if (expansion_opportunity_count)
-    inset = std::min(LayoutUnit(2 * StyleRef().FontSize()), inset);
-
-  logical_left += inset / 2;
-  logical_width -= inset;
-}
-
 }  // namespace blink

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

@@ -54,13 +54,6 @@ class LayoutRubyText : public LayoutBlockFlow {
     // ruby text objects.
     return true;
   }
-
- private:
-  ETextAlign TextAlignmentForLine(bool ends_with_soft_break) const override;
-  void AdjustInlineDirectionLineBounds(
-      unsigned expansion_opportunity_count,
-      LayoutUnit& logical_left,
-      LayoutUnit& logical_width) const override;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutRubyText, IsRubyText());

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

@@ -939,6 +939,7 @@ LayoutRect LayoutText::LocalCaretRect(
     case ETextAlign::kWebkitCenter:
       break;
     case ETextAlign::kJustify:
+    case ETextAlign::kInternalSpaceAround:
     case ETextAlign::kStart:
       right_aligned = !cb_style.IsLeftToRightDirection();
       break;
@@ -1673,7 +1674,8 @@ bool LayoutText::CanOptimizeSetText() const {
          // We would need to recompute the position if "direction" is "rtl".
          StyleRef().IsLeftToRightDirection() &&
          // We would need to layout the text if it is justified.
-         (StyleRef().GetTextAlign(true) != ETextAlign::kJustify);
+         (StyleRef().GetTextAlign(true) != ETextAlign::kJustify &&
+          StyleRef().GetTextAlign(true) != ETextAlign::kInternalSpaceAround);
 }
 
 void LayoutText::SetFirstTextBoxLogicalLeft(float text_width) const {
@@ -1691,6 +1693,7 @@ void LayoutText::SetFirstTextBoxLogicalLeft(float text_width) const {
       case ETextAlign::kLeft:
       case ETextAlign::kWebkitLeft:
       case ETextAlign::kJustify:
+      case ETextAlign::kInternalSpaceAround:
       case ETextAlign::kStart:
         // Do nothing.
         break;