add helper to create fancy underlines

src/core/SkGlyphCache.h

 /*
  * 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.
  */
 
 #ifndef SkGlyphCache_DEFINED
 #define SkGlyphCache_DEFINED
 
 #include "SkBitmap.h"
@@ skipping 59 matching lines @@
     unsigned getGlyphCount() const;
 
     /** Return the number of glyphs currently cached. */
     int countCachedGlyphs() const;
 
     /** Return the image associated with the glyph. If it has not been generated this will
         trigger that.
     */
     const void* findImage(const SkGlyph&);
 
+    /** If the advance axis intersects the glyph's path, append the positions scaled and offset
+        to the array (if non-null), and set the count to the updated array length.
+    */
+    void findIntercepts(const SkScalar bounds[2], SkScalar scale, SkScalar xPos,
+                        bool yAxis, SkGlyph* , SkScalar* array, int* count);
+
     /** Return the Path associated with the glyph. If it has not been generated this will trigger
         that.
     */
     const SkPath* findPath(const SkGlyph&);
 
     /** Return the vertical metrics for this strike.
     */
     const SkPaint::FontMetrics& getFontMetrics() const {
         return fFontMetrics;
     }
@@ skipping 225 matching lines @@
                             const SkMatrix* matrix) {
         fCache = paint.detachCache(surfaceProps, matrix, true);
     }
 
 private:
     SkAutoGlyphCacheNoGamma() : SkAutoGlyphCacheBase() {}
 };
 #define SkAutoGlyphCacheNoGamma(...) SK_REQUIRE_LOCAL_VAR(SkAutoGlyphCacheNoGamma)
 
 #endif