OWNERS files updated with latest COMPONENT and TEAMS.

This is CL is generated by a script. Data is pulled from
review conducted in Q2 2019. See https://tinyurl.com/yxau5sc4
for context.

Bug: 977050
Change-Id: Ia891d4988299e76925beb57bc69c22e19187eaa1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1700872Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Commit-Queue: Eric Foo <efoo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691005}

chrome/browser/browser_switcher/OWNERS

 nicolaso@chromium.org
 pastarmovj@chromium.org
+# COMPONENT: Enterprise>BrowserSwitcher

chromeos/components/nearby/OWNERS

 khorimoto@chromium.org
 hansberry@chromium.org
 reznor@chromium.org
+# COMPONENT: UI>Multidevice

chromeos/process_proxy/OWNERS

 tbarzic@chromium.org
+# COMPONENT: Internals

extensions/browser/api/OWNERS

 # For Chrome OS apps APIs.
 tbarzic@chromium.org
+# COMPONENT: Platform>Extensions>API