[SkSVGDevice] Full font family support

Use a family name iterator and list all names instead of just one
returned by SkTypeface::getFamilyName().

R=reed@google.com,mtklein@google.com

Review URL: https://codereview.chromium.org/923583002
diff --git a/gyp/svg.gyp b/gyp/svg.gyp
index d681bda..82ff53d 100644
--- a/gyp/svg.gyp
+++ b/gyp/svg.gyp
@@ -11,6 +11,7 @@
       ],
       'include_dirs': [
         '../include/svg',
+        '../src/core',
       ],
       'sources': [
         '<(skia_include_path)/svg/SkSVGCanvas.h',