Vertically center multi-line RenderTextHarfBuzz that uses SetMinLineHeight().

ui/gfx/render_text.h

 // Copyright (c) 2012 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 UI_GFX_RENDER_TEXT_H_
 #define UI_GFX_RENDER_TEXT_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 662 matching lines @@
   // the text bounds. Returns -1 if |text_y| is above the text and
   // lines().size() if |text_y| is below it.
   int GetLineContainingYCoord(float text_y);
 
   // A convenience function to check whether the glyph attached to the caret
   // is within the given range.
   static bool RangeContainsCaret(const Range& range,
                                  size_t caret_pos,
                                  LogicalCursorDirection caret_affinity);
 
+  // Returns the baseline, with which the text best appears vertically centered.
+  static int DetermineBaselineCenteringText(const int display_height,
+                                            const FontList& font_list);
+
  private:
   friend class test::RenderTextTestApi;
 
   // Set the cursor to |position|, with the caret trailing the previous
   // grapheme, or if there is no previous grapheme, leading the cursor position.
   // If |select| is false, the selection start is moved to the same position.
   // If the |position| is not a cursorable position (not on grapheme boundary),
   // it is a NO-OP.
   void MoveCursorTo(size_t position, bool select);
 
@@ skipping 160 matching lines @@
   // Lines computed by EnsureLayout. These should be invalidated upon
   // OnLayoutTextAttributeChanged and OnDisplayTextAttributeChanged calls.
   std::vector<internal::Line> lines_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderText);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_H_