[LayoutNG] Add box fragments to line boxes when needed

third_party/WebKit/Source/core/layout/ng/inline/ng_inline_box_state.h

Index: third_party/WebKit/Source/core/layout/ng/inline/ng_inline_box_state.h
diff --git a/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_box_state.h b/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_box_state.h
index 96106abe612ef2777e8305b03bad9fd8e5eb5db0..5fcc3965dfa99454c662e3729255ee234a1d4b2f 100644
--- a/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_box_state.h
+++ b/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_box_state.h
@@ -6,6 +6,7 @@
 #define NGInlineBoxState_h
 
 #include "core/CoreExport.h"
+#include "core/layout/ng/geometry/ng_logical_size.h"
 #include "core/layout/ng/inline/ng_line_height_metrics.h"
 #include "core/style/ComputedStyleConstants.h"
 #include "platform/LayoutUnit.h"
@@ -16,7 +17,6 @@ namespace blink {
 
 class NGInlineItem;
 class NGLineBoxFragmentBuilder;
-class NGTextFragmentBuilder;
 
 // Fragments that require the layout position/size of ancestor are packed in
 // this struct.
@@ -32,12 +32,21 @@ struct NGPendingPositions {
 // require ancestor position or size.
 struct NGInlineBoxState {
   unsigned fragment_start;
+  const NGInlineItem* item;
   const ComputedStyle* style;
   NGLineHeightMetrics metrics;
   NGLineHeightMetrics text_metrics;
   LayoutUnit text_top;
+
+  // These values are to create a box fragment. Set only when needs_box_fragment
+  // is set.
+  LayoutUnit line_left_position;
+  LayoutUnit borders_paddings_block_start;
+  LayoutUnit borders_paddings_block_height;
+
   Vector<NGPendingPositions> pending_descendants;
   bool include_used_fonts = false;
+  bool needs_box_fragment = false;
 
   // Compute text metrics for a box. All text in a box share the same metrics.
   void ComputeTextMetrics(const ComputedStyle& style, FontBaseline);
@@ -45,6 +54,11 @@ struct NGInlineBoxState {
                            unsigned start,
                            unsigned end,
                            FontBaseline);
+
+  // Create a box fragment for this box.
+  void SetNeedsBoxFragment(LayoutUnit line_left_position,
+                           LayoutUnit borders_paddings_block_start,
+                           LayoutUnit borders_paddings_block_height);
 };
 
 // Represents the inline tree structure. This class provides:
@@ -61,23 +75,33 @@ class NGInlineLayoutStateStack {
   NGInlineBoxState* OnBeginPlaceItems(const ComputedStyle*, FontBaseline);
 
   // Push a box state stack.
-  NGInlineBoxState* OnOpenTag(const NGInlineItem&,
-                              NGLineBoxFragmentBuilder*,
-                              NGTextFragmentBuilder*);
+  NGInlineBoxState* OnOpenTag(const NGInlineItem&, NGLineBoxFragmentBuilder*);
 
   // Pop a box state stack.
   NGInlineBoxState* OnCloseTag(const NGInlineItem&,
                                NGLineBoxFragmentBuilder*,
                                NGInlineBoxState*,
-                               FontBaseline);
+                               FontBaseline,
+                               LayoutUnit position);
 
   // Compute all the pending positioning at the end of a line.
-  void OnEndPlaceItems(NGLineBoxFragmentBuilder*, FontBaseline);
+  void OnEndPlaceItems(NGLineBoxFragmentBuilder*,
+                       FontBaseline,
+                       LayoutUnit position);
 
  private:
   // End of a box state, either explicitly by close tag, or implicitly at the
   // end of a line.
-  void EndBoxState(NGInlineBoxState*, NGLineBoxFragmentBuilder*, FontBaseline);
+  void EndBoxState(NGInlineBoxState*,
+                   NGLineBoxFragmentBuilder*,
+                   FontBaseline,
+                   LayoutUnit position);
+
+  void AddBoxFragmentPlaceholder(NGInlineBoxState*,
+                                 NGLineBoxFragmentBuilder*,
+                                 FontBaseline,
+                                 LayoutUnit position);
+  void CreateBoxFragments(NGLineBoxFragmentBuilder*);
 
   enum PositionPending { kPositionNotPending, kPositionPending };
 
@@ -91,7 +115,16 @@ class NGInlineLayoutStateStack {
                                      NGLineBoxFragmentBuilder*,
                                      FontBaseline);
 
+  // Data for a box fragment placeholder. See AddBoxFragmentPlaceholder().
+  struct BoxFragmentPlaceholder {
+    unsigned fragment_start;
+    unsigned fragment_end;
+    const NGInlineItem* item;
+    NGLogicalSize size;
+  };
+
   Vector<NGInlineBoxState, 4> stack_;
+  Vector<BoxFragmentPlaceholder, 4> box_placeholders_;
 };
 
 }  // namespace blink