Update existing uses of /wd4267 to use the GN config

components/packed_ct_ev_whitelist/BUILD.gn

Index: components/packed_ct_ev_whitelist/BUILD.gn
diff --git a/components/packed_ct_ev_whitelist/BUILD.gn b/components/packed_ct_ev_whitelist/BUILD.gn
index ae9561ea1aa2e9254c6dd76ba9c9748a802d68f6..c3ca36c9d23daf458e5ceacdcee5e4c2eb97c8cb 100644
--- a/components/packed_ct_ev_whitelist/BUILD.gn
+++ b/components/packed_ct_ev_whitelist/BUILD.gn
@@ -10,16 +10,13 @@ static_library("packed_ct_ev_whitelist") {
     "packed_ct_ev_whitelist.h",
   ]
 
+  configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
+
   deps = [
     "//base",
     "//content",
     "//net",
   ]
-
-  if (is_win) {
-    # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-    cflags = [ "/wd4267" ]
-  }
 }
 
 source_set("unit_tests") {