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diff --git a/chromium/third_party/blink/renderer/platform/fonts/shaping/stretchy_operator_shaper.h b/chromium/third_party/blink/renderer/platform/fonts/shaping/stretchy_operator_shaper.h
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+++ b/chromium/third_party/blink/renderer/platform/fonts/shaping/stretchy_operator_shaper.h
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+// Copyright 2020 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_STRETCHY_OPERATOR_SHAPER_H_
+#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_STRETCHY_OPERATOR_SHAPER_H_
+
+#include <base/memory/scoped_refptr.h>
+#include <unicode/uchar.h>
+#include "third_party/blink/renderer/platform/fonts/glyph.h"
+#include "third_party/blink/renderer/platform/fonts/opentype/open_type_math_support.h"
+#include "third_party/blink/renderer/platform/text/text_direction.h"
+#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
+
+namespace blink {
+
+class Font;
+class ShapeResult;
+class StretchyOperatorShaper;
+
+// TODO(https://crbug.com/1057589): Add a TextDirection parameter, so that it's
+// possible to perform glyph-level (rtlm feature) or character-level mirroring
+// before stretching.
+// https://mathml-refresh.github.io/mathml-core/#algorithms-for-glyph-stretching
+class PLATFORM_EXPORT StretchyOperatorShaper final {
+  DISALLOW_NEW();
+
+ public:
+  StretchyOperatorShaper(UChar stretchy_character,
+                         OpenTypeMathStretchData::StretchAxis stretch_axis)
+      : stretchy_character_(stretchy_character), stretch_axis_(stretch_axis) {}
+
+  // Returns the metrics of the stretched operator for layout purpose.
+  // May be called multiple times; font and direction may vary between calls.
+  // https://mathml-refresh.github.io/mathml-core/#dfn-box-metrics-of-a-stretchy-glyph
+  struct Metrics {
+    float advance;
+    float ascent;
+    float descent;
+    // TODO(https://crbug.com/1057592): Add italic correction.
+  };
+  Metrics GetMetrics(const Font*, float target_size) const;
+
+  // Shape the stretched operator. The coordinates of the glyph(s) use the same
+  // origin as the rectangle returned by GetMetrics.
+  // May be called multiple times; font and direction may vary between calls.
+  // https://mathml-refresh.github.io/mathml-core/#dfn-shape-a-stretchy-glyph
+  scoped_refptr<ShapeResult> Shape(const Font*, float target_size) const;
+
+  ~StretchyOperatorShaper() = default;
+
+ private:
+  const UChar stretchy_character_;
+  const OpenTypeMathStretchData::StretchAxis stretch_axis_;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_STRETCHY_OPERATOR_SHAPER_H_