remove clipbounds flag

BUG=skia:

Change-Id: I55b3098abd5e566e9f8bf27988c33e531d2ea54d
Reviewed-on: https://skia-review.googlesource.com/7618
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/public.bzl b/public.bzl
index 72f33b3..14d0c53 100644
--- a/public.bzl
+++ b/public.bzl
@@ -590,7 +590,6 @@
     "SK_NO_ANALYTIC_AA",
     "SK_SUPPORT_LEGACY_BITMAP_SETPIXELREF",
     "SK_SUPPORT_LEGACY_CLIPOP_EXOTIC_NAMES",
-    "SK_SUPPORT_LEGACY_GETCLIPBOUNDS",
 ]
 
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