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The new Delegate class is called to open the connected device
settings UI.

This refactor is allows:
  * logging the current screen when the button is pressed
  * a unit test case for pressing the settings button

BUG=1138137,1106937

Change-Id: I71af2ec6c00813536c15f684fdb8459f4671cada
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2501072Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821352}