[Picture-in-Picture] Add metrics for window controls

This CL record buttons pressed and tap gestures for all controls in the
Picture-in-Picture window.

Bug: 932410
Change-Id: Ie751322f7e4fe3026a47e95c1a839cb90e2ae85b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1475433
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: François Beaufort 🦔 <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/heads/master@{#637599}
4 files changed