vertices to/from data

precursor to enabling serialization in pictures

BUG=skia:6366

Change-Id: Iba89aa98f389b3281e7705d041e3337e89071f03
Reviewed-on: https://skia-review.googlesource.com/9680
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/gn/tests.gni b/gn/tests.gni
index 1e9fb0e..b2a814e 100644
--- a/gn/tests.gni
+++ b/gn/tests.gni
@@ -247,6 +247,7 @@
   "$_tests/UnicodeTest.cpp",
   "$_tests/UtilsTest.cpp",
   "$_tests/VarAllocTest.cpp",
+  "$_tests/VerticesTest.cpp",
   "$_tests/VkClearTests.cpp",
   "$_tests/VkHeapTests.cpp",
   "$_tests/VkUploadPixelsTests.cpp",