Add full offset mapping construction in a block

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

Index: third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node.h
diff --git a/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node.h b/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node.h
index 11a28ba9b77334120000b7e7fb136a0b845828fa..107c5a89625714c9ea53e6adeed9999acc1d2914 100644
--- a/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node.h
+++ b/third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node.h
@@ -28,6 +28,7 @@ class NGInlineItemRange;
 using NGInlineItemsBuilder =
     NGInlineItemsBuilderTemplate<EmptyOffsetMappingBuilder>;
 class NGLayoutResult;
+struct NGOffsetMappingResult;
 
 // Represents an anonymous block box to be laid out, that contains consecutive
 // inline nodes and their descendants.
@@ -64,6 +65,10 @@ class CORE_EXPORT NGInlineNode : public NGLayoutInputNode {
 
   void GetLayoutTextOffsets(Vector<unsigned, 32>*);
 
+  // Returns the DOM to text content offset mapping of this block. Must be
+  // called with clean layout.
+  NGOffsetMappingResult BuildOffsetMapping() const;
+
   bool IsBidiEnabled() const { return Data().is_bidi_enabled_; }
   TextDirection BaseDirection() const { return Data().BaseDirection(); }