Add estade to chrome/browser/ui/views/page_action/OWNERS

PageActionIconViews in chrome/browser/ui/views/location_bar will get migrated
to chrome/browser/ui/views/page_action as part of crbug.com/788051.
This CL adds estade, an OWNER of location_bar, to the OWNERS of page_action.
pkasting is not being added because they have higher level OWNERS and
requested not to be added to the new directory.

Change-Id: Ia400f3b74e0cadcb719990a22a542a848d07c999
Reviewed-on: https://chromium-review.googlesource.com/1065410Reviewed-by: Evan Stade <estade@chromium.org>
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560867}

chrome/browser/ui/views/page_action/OWNERS

 alancutter@chromium.org
 calamity@chromium.org
+estade@chromium.org
 
 # COMPONENT: UI>Browser>Bubbles
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