Fix the B2G viewer and enable bot preview.
Fix bot breakage caused by Chromium extension PR
Merge pull request #3794 from brendandahl/b2g-fix

Fix the B2G viewer and enable bot preview.
Merge pull request #3822 from Snuffleupagus/fix-chromium-PR-bot-breakage

Fix bot breakage caused by Chromium extension PR
Decrease dependence of SecondaryToolbar on UI buttons
Merge pull request #3821 from timvandermeij/secondary-toolbar-elements

Decrease dependence of SecondaryToolbar on UI buttons