SkPDF/SkAdvancedTypefaceMetrics: simplify ATM, PDF takes over

src/pdf/SkPDFFontImpl.h

Index: src/pdf/SkPDFFontImpl.h
diff --git a/src/pdf/SkPDFFontImpl.h b/src/pdf/SkPDFFontImpl.h
index 0dfa19189cbbfd5e2c2da0263fbaf5cc74bd1bc8..05774de6b39a7b2e01e3ba7fecb549de00425abe 100644
--- a/src/pdf/SkPDFFontImpl.h
+++ b/src/pdf/SkPDFFontImpl.h
@@ -52,6 +52,8 @@ private:
                            const SkTDArray<uint32_t>* subset);
 };
 
+struct AdvanceMetric;
+
 class SkPDFType1Font final : public SkPDFFont {
 public:
     virtual ~SkPDFType1Font();
@@ -68,7 +70,7 @@ private:
     bool populate(int16_t glyphID);
     bool addFontDescriptor(int16_t defaultWidth);
     void addWidthInfoFromRange(int16_t defaultWidth,
-        const SkAdvancedTypefaceMetrics::WidthRange* widthRangeEntry);
+        const AdvanceMetric* widthRangeEntry);
 };
 
 class SkPDFType3Font final : public SkPDFFont {