Make NGInlineItemsBuilder construct whitespace-collapsed offset mapping

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NGInlineItemsBuilder_h
 #define NGInlineItemsBuilder_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/inline/ng_inline_node.h"
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/Vector.h"
 #include "platform/wtf/text/StringBuilder.h"
 #include "platform/wtf/text/WTFString.h"
 
 namespace blink {
 
 class ComputedStyle;
 class LayoutObject;
 class NGInlineItem;
+class NGOffsetMappingBuilder;
 
 // NGInlineItemsBuilder builds a string and a list of NGInlineItem from inlines.
 //
 // When appending, spaces are collapsed according to CSS Text, The white space
 // processing rules
 // https://drafts.csswg.org/css-text-3/#white-space-rules
 //
 // By calling EnterInline/ExitInline, it inserts bidirectional control
 // characters as defined in:
 // https://drafts.csswg.org/css-writing-modes-3/#bidi-control-codes-injection-table
+//
+// NGInlineItemsBuilder may optionally take an NGOffsetMappingBuilder parameter
+// to construct the white-space collapsed offset mapping, which maps offsets in
+// the concatenation of all appended strings and characters to offsets in
+// |text_|. See https://goo.gl/CJbxky for more details about offset mapping.
 class CORE_EXPORT NGInlineItemsBuilder {
   STACK_ALLOCATED();
 
  public:
-  explicit NGInlineItemsBuilder(Vector<NGInlineItem>* items) : items_(items) {}
+  explicit NGInlineItemsBuilder(Vector<NGInlineItem>* items)
+      : items_(items), mapping_builder_(nullptr) {}
+  explicit NGInlineItemsBuilder(Vector<NGInlineItem>* items,
+                                NGOffsetMappingBuilder* mapping_builder)
+      : items_(items), mapping_builder_(mapping_builder) {}
   ~NGInlineItemsBuilder();
 
   String ToString();
 
   void SetIsSVGText(bool value) { is_svgtext_ = value; }
 
   // Returns whether the items contain any Bidi controls.
   bool HasBidiControls() const { return has_bidi_controls_; }
 
   // Append a string.
@@ skipping 46 matching lines @@
     UChar character;
   } OnExitNode;
   Vector<OnExitNode> exits_;
 
   enum class CollapsibleSpace { kNone, kSpace, kNewline };
 
   CollapsibleSpace last_collapsible_space_ = CollapsibleSpace::kSpace;
   bool is_svgtext_ = false;
   bool has_bidi_controls_ = false;
 
+  NGOffsetMappingBuilder* mapping_builder_;
+
   void AppendWithWhiteSpaceCollapsing(const String&,
                                       unsigned start,
                                       unsigned end,
                                       const ComputedStyle*,
                                       LayoutObject*);
   void AppendWithoutWhiteSpaceCollapsing(const String&,
                                          const ComputedStyle*,
                                          LayoutObject*);
   void AppendWithPreservingNewlines(const String&,
                                     const ComputedStyle*,
@@ skipping 13 matching lines @@
                                                 unsigned,
                                                 const ComputedStyle*);
 
   void Enter(LayoutObject*, UChar);
   void Exit(LayoutObject*);
 };
 
 }  // namespace blink
 
 #endif  // NGInlineItemsBuilder_h