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/empty_offset_mapping_builder.h"
 #include "core/layout/ng/inline/ng_inline_node.h"
+#include "core/layout/ng/inline/ng_offset_mapping_builder.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;
 
 // 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
-// TODO(xiaochengh): Utilize the passed-in OffsetMappingBuilder to construct
-// the whitespace-collapsed offset mapping.
+//
+// NGInlineItemsBuilder may optionally take an NGOffsetMappingBuilder template
+// 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.
 template <typename OffsetMappingBuilder>
 class CORE_TEMPLATE_CLASS_EXPORT NGInlineItemsBuilderTemplate {
   STACK_ALLOCATED();
 
  public:
   explicit NGInlineItemsBuilderTemplate(Vector<NGInlineItem>* items)
       : items_(items) {}
   ~NGInlineItemsBuilderTemplate();
 
   String ToString();
@@ skipping 37 matching lines @@
                     LayoutObject* = nullptr);
 
   // Append a Bidi control character, for LTR or RTL depends on the style.
   void AppendBidiControl(const ComputedStyle*, UChar ltr, UChar rtl);
 
   void EnterBlock(const ComputedStyle*);
   void ExitBlock();
   void EnterInline(LayoutObject*);
   void ExitInline(LayoutObject*);
 
+  OffsetMappingBuilder& GetOffsetMappingBuilder() { return mapping_builder_; }
+
  private:
   Vector<NGInlineItem>* items_;
   StringBuilder text_;
+  OffsetMappingBuilder mapping_builder_;
 
   typedef struct OnExitNode {
     LayoutObject* node;
     UChar character;
   } OnExitNode;
   Vector<OnExitNode> exits_;
 
   enum class CollapsibleSpace { kNone, kSpace, kNewline };
 
   CollapsibleSpace last_collapsible_space_ = CollapsibleSpace::kSpace;
@@ skipping 19 matching lines @@
   void RemoveTrailingCollapsibleNewlineIfNeeded(const String&,
                                                 unsigned,
                                                 const ComputedStyle*);
 
   void Enter(LayoutObject*, UChar);
   void Exit(LayoutObject*);
 };
 
 extern template class CORE_EXTERN_TEMPLATE_EXPORT
     NGInlineItemsBuilderTemplate<EmptyOffsetMappingBuilder>;
+extern template class CORE_EXTERN_TEMPLATE_EXPORT
+    NGInlineItemsBuilderTemplate<NGOffsetMappingBuilder>;
 
 using NGInlineItemsBuilder =
     NGInlineItemsBuilderTemplate<EmptyOffsetMappingBuilder>;
+using NGInlineItemsBuilderForOffsetMapping =
+    NGInlineItemsBuilderTemplate<NGOffsetMappingBuilder>;
 
 }  // namespace blink
 
 #endif  // NGInlineItemsBuilder_h