Implement SkScalerContext_DW::generateColorMetrics(SkGlyph* glyph) on Windows.

Fix layout problem for color glyph.

BUG=chromium:698492
Change-Id: Iff586332ee0d7fdbf8c6c7f340536855b753769c
Reviewed-on: https://skia-review.googlesource.com/134519
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/src/ports/SkScalerContext_win_dw.h b/src/ports/SkScalerContext_win_dw.h
index 430048c..d5a217d 100644
--- a/src/ports/SkScalerContext_win_dw.h
+++ b/src/ports/SkScalerContext_win_dw.h
@@ -52,7 +52,9 @@
     }
 
     bool getColorGlyphRun(const SkGlyph& glyph, IDWriteColorGlyphRunEnumerator** colorGlyph);
-
+    
+    void generateColorMetrics(SkGlyph* glyph);
+    
     void generateColorGlyphImage(const SkGlyph& glyph);
 
     SkTDArray<uint8_t> fBits;