allow renderer/core OWNERS to approve blink finch flags

Change-Id: If3cafee7b0627d3b930e63f975a793d7bee8c421
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2468790Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: David Grogan <dgrogan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816771}

third_party/blink/common/OWNERS

@@ -9,4 +9,7 @@ kinuko@chromium.org
 pfeldman@chromium.org
 tkent@chromium.org
 
+# Any core owner can approve blink finch flags.
+per-file features.cc=file://third_party/blink/renderer/core/OWNERS
+
 # COMPONENT: Blink

third_party/blink/public/common/OWNERS

+# Any core owner can approve blink finch flags.
+per-file features.h=file://third_party/blink/renderer/core/OWNERS
+
+# TEAM: platform-architecture-dev@chromium.org
+# COMPONENT: Blink>Internals>Modularization