SkCustomTypeface tweaks

  - don't require prior glyph count knowledge - grow dynamically

  - no need to store the glyph count explicitly, it's reflected in
    path/advance vector sizes

Change-Id: I3650ba9312db02c99b72bcf7fd3215697ec00b08
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/289893
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
diff --git a/gm/userfont.cpp b/gm/userfont.cpp
index c803373..ed20109 100644
--- a/gm/userfont.cpp
+++ b/gm/userfont.cpp
@@ -16,7 +16,7 @@
 #include "tools/Resources.h"
 
 static sk_sp<SkTypeface> make_tf() {
-    SkCustomTypefaceBuilder builder(128);
+    SkCustomTypefaceBuilder builder;
     SkFont font;
     font.setSize(1.0f);
     font.setHinting(SkFontHinting::kNone);