Templatize NGInlineItemsBuilder to take a OffsetMappingBuilder parameter

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/api/empty_offset_mapping_builder.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;
 
 // 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
-class CORE_EXPORT NGInlineItemsBuilder {
+// TODO(xiaochengh): Pass in a real offset mapping builder type and use it to
+// construct the whitespace-collapsed offset mapping.
+template <typename OffsetMappingBuilder>
+class CORE_TEMPLATE_CLASS_EXPORT NGInlineItemsBuilderTemplate {
   STACK_ALLOCATED();
 
  public:
-  explicit NGInlineItemsBuilder(Vector<NGInlineItem>* items) : items_(items) {}
-  ~NGInlineItemsBuilder();
+  explicit NGInlineItemsBuilderTemplate(Vector<NGInlineItem>* items)
+      : items_(items) {}
+  ~NGInlineItemsBuilderTemplate();
 
   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.
   // When appending, spaces are collapsed according to CSS Text, The white space
@@ skipping 32 matching lines @@
   void AppendBidiControl(const ComputedStyle*, UChar ltr, UChar rtl);
 
   void EnterBlock(const ComputedStyle*);
   void ExitBlock();
   void EnterInline(LayoutObject*);
   void ExitInline(LayoutObject*);
 
  private:
   Vector<NGInlineItem>* items_;
   StringBuilder text_;
+  OffsetMappingBuilder mapping_builder_;

[yosin_UTC9, 2017/06/28 03:37:11]

Could you upload the patch which using |mapping_builder_|?
It seems this patch doesn't have use sites of |mapping_builder_|.

[Xiaocheng, 2017/06/28 03:44:42]

This is just a preparation patch that templatizes NGInlineItemsBuilder, but does
not do anything with the template parameter.

Use sites of the mapping builder are introduced in
https://codereview.chromium.org/2943573002/.

Maybe I should even remove |mapping_builder_| in this patch, and put it in the
follow-up one?

 
   typedef struct OnExitNode {
     LayoutObject* node;
     UChar character;
   } OnExitNode;
   Vector<OnExitNode> exits_;
 
   enum class CollapsibleSpace { kNone, kSpace, kNewline };
 
   CollapsibleSpace last_collapsible_space_ = CollapsibleSpace::kSpace;
@@ skipping 23 matching lines @@
   void RemoveTrailingCollapsibleSpaceIfExists();
   void RemoveTrailingCollapsibleSpace(unsigned);
   void RemoveTrailingCollapsibleNewlineIfNeeded(const String&,
                                                 unsigned,
                                                 const ComputedStyle*);
 
   void Enter(LayoutObject*, UChar);
   void Exit(LayoutObject*);
 };
 
+extern template class CORE_EXTERN_TEMPLATE_EXPORT
+    NGInlineItemsBuilderTemplate<EmptyOffsetMappingBuilder>;
+
+using NGInlineItemsBuilder =
+    NGInlineItemsBuilderTemplate<EmptyOffsetMappingBuilder>;
+
 }  // namespace blink
 
 #endif  // NGInlineItemsBuilder_h