Add blundell to //chrome OWNERS

Change-Id: I7ad4f41c3af77ea60587555f87a493462305bba6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1520597Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641121}

chrome/OWNERS

@@ -2,6 +2,7 @@
 # where possible.
 
 # Reviewers (in CET):
+blundell@chromium.org
 droger@chromium.org
 treib@chromium.org
 vasilii@chromium.org