add helper to create fancy underlines

src/core/SkGlyphCache.h

Index: src/core/SkGlyphCache.h
diff --git a/src/core/SkGlyphCache.h b/src/core/SkGlyphCache.h
index 2f1f417250eda9aae45b62e614eb158afdb37048..cd0b05c6e960adc862d94946efa95046c8dafb23 100644
--- a/src/core/SkGlyphCache.h
+++ b/src/core/SkGlyphCache.h
@@ -77,6 +77,12 @@ public:
     */
     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.
     */
@@ -232,6 +238,20 @@ private:
 
     inline static SkGlyphCache* FindTail(SkGlyphCache* head);
 
+    static void OffsetResults(const SkGlyph::Intercept* intercept, SkScalar scale,
+                              SkScalar xPos, SkScalar* array, int* count);
+    static void AddInterval(SkScalar val, SkGlyph::Intercept* intercept);
+    static void AddPoints(const SkPoint* pts, int ptCount, const SkScalar bounds[2], 
+                          bool yAxis, SkGlyph::Intercept* intercept);
+    static void AddLine(const SkPoint pts[2], SkScalar axis, bool yAxis,
+                        SkGlyph::Intercept* intercept);
+    static void AddQuad(const SkPoint pts[2], SkScalar axis, bool yAxis,
+                        SkGlyph::Intercept* intercept);
+    static void AddCubic(const SkPoint pts[3], SkScalar axis, bool yAxis,
+                         SkGlyph::Intercept* intercept);
+    static const SkGlyph::Intercept* MatchBounds(const SkGlyph* glyph,
+                                                 const SkScalar bounds[2]);
+
     SkGlyphCache*          fNext;
     SkGlyphCache*          fPrev;
     SkDescriptor* const    fDesc;