First pass at changing the viewport selector to drop-down.

Change-Id: I33e2106ae4a17a9ea9912c93f0ad79f6c2534f3a
Merge topic 'pvwev-select-box-for-viewport-selection' into next

05d7e09 First pass at changing the viewport selector to drop-down.
Remove image button.

Change-Id: Ieca5c5d6b26cd7d7ffd778e67bd79950762df1e6
Merge topic 'pvwev-select-box-for-viewport-selection' into next

e7c04ef Remove image button.