Use typographic font metrics when the font requests.

src/ports/SkFontHost_FreeType.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAdvancedTypefaceMetrics.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 1297 matching lines @@
         avgCharWidth = SkIntToScalar(os2->xAvgCharWidth) / upem;
         if (os2->version != 0xFFFF && os2->version >= 2) {
             cap_height = scaleX * SkIntToScalar(os2->sCapHeight) / upem;
         }
     }
 
     // pull from format-specific metrics as needed
     SkScalar ascent, descent, leading, xmin, xmax, ymin, ymax;
     SkScalar underlineThickness, underlinePosition;
     if (face->face_flags & FT_FACE_FLAG_SCALABLE) { // scalable outline font
-        ascent = -SkIntToScalar(face->ascender) / upem;
-        descent = -SkIntToScalar(face->descender) / upem;
-        leading = SkIntToScalar(face->height + (face->descender - face->ascender)) / upem;
+        // FreeType will always use HHEA metrics if they're not zero.
+        // It completely ignores the OS/2 fsSelection::UseTypoMetrics bit.
+        // It also ignores the VDMX tables, which are also of interest here
+        // (and override everything else when they apply).
+        static const int kUseTypoMetricsMask = (1 << 7);
+        if (os2 && os2->version != 0xFFFF && (os2->fsSelection & kUseTypoMetricsMask)) {
+            ascent = -SkIntToScalar(os2->sTypoAscender) / upem;
+            descent = -SkIntToScalar(os2->sTypoDescender) / upem;
+            leading = SkIntToScalar(os2->sTypoLineGap) / upem;
+        } else {
+            ascent = -SkIntToScalar(face->ascender) / upem;
+            descent = -SkIntToScalar(face->descender) / upem;
+            leading = SkIntToScalar(face->height + (face->descender - face->ascender)) / upem;
+        }
         xmin = SkIntToScalar(face->bbox.xMin) / upem;
         xmax = SkIntToScalar(face->bbox.xMax) / upem;
         ymin = -SkIntToScalar(face->bbox.yMin) / upem;
         ymax = -SkIntToScalar(face->bbox.yMax) / upem;
         underlineThickness = SkIntToScalar(face->underline_thickness) / upem;
         underlinePosition = -SkIntToScalar(face->underline_position +
                                            face->underline_thickness / 2) / upem;
 
         metrics->fFlags |= SkPaint::FontMetrics::kUnderlineThinknessIsValid_Flag;
         metrics->fFlags |= SkPaint::FontMetrics::kUnderlinePositionIsValid_Flag;
@@ skipping 379 matching lines @@
     if (style) {
         *style = SkFontStyle(weight, width, slant);
     }
     if (isFixedPitch) {
         *isFixedPitch = FT_IS_FIXED_WIDTH(face);
     }
 
     FT_Done_Face(face);
     return true;
 }