remove bunch of legacy flags

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4203

Change-Id: I0e23437a77cd8f70595ca54ae421a420e2bb9b43
Reviewed-on: https://skia-review.googlesource.com/4203
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/public.bzl b/public.bzl
index 5f3d73d..7c54ee7 100644
--- a/public.bzl
+++ b/public.bzl
@@ -600,19 +600,7 @@
     "GOOGLE3",
     # Staging flags for API changes
     "SK_SUPPORT_LEGACY_ACCESSBITMAP",
-    "SK_SUPPORT_LEGACY_ARITHMETICMODE",
-    "SK_SUPPORT_LEGACY_IMAGEFACTORY",
-    "SK_SUPPORT_LEGACY_MASKFILTER_PTR",
-    "SK_SUPPORT_LEGACY_MINOR_EFFECT_PTR",
-    "SK_SUPPORT_LEGACY_NEW_SURFACE_API",
-    "SK_SUPPORT_LEGACY_PATHEFFECT_PTR",
-    "SK_SUPPORT_LEGACY_PICTURE_PTR",
-    "SK_SUPPORT_LEGACY_TYPEFACE_PTR",
-    "SK_SUPPORT_LEGACY_PICTUREINSTALLPIXELREF",
-    "SK_SUPPORT_LEGACY_STREAM_DATA",
     "SK_SUPPORT_LEGACY_CLIP_REGIONOPS",
-    "SK_SUPPORT_LEGACY_SHADER_ISABITMAP",
-    "SK_SUPPORT_LEGACY_XFERMODE_OBJECT",
     "SK_SUPPORT_LEGACY_COLOR_SPACE_FACTORIES",
     "SK_SUPPORT_LEGACY_SHADER_ASALOCALMATRIXSHADER",
     "SK_SUPPORT_LEGACY_XFERMODE_PARAM",