Bug 846772 - Add prefs observing to PrefsHelper/browser.js on Android. r=kats
Bug 846772 - Observe dynamic toolbar pref on Android. r=kats

Respond to this pref changing instantly instead of requiring a restart.
Bug 846772 - Disable dynamic toolbar on robocop tests. r=kats,jmaher

Pretty much all of the robocop tests that involve input assumed a static UI.
Making them compatible with the dynamic toolbar would require a considerable
rethink, so turn it off by default. We can introduce robocop tests specifically
for the dynamic toolbar later.
Bug 846772 - Fuzz dynamic-clipPath-01 and scroll-rounding tests for Android. r=jwatt,matspal

These tests need extra fuzzing when the dynamic toolbar is enabled.
Bug 846772 - Enable dynamic toolbar by default on Android. r=kats
Bug 805479 - When calculating the initial fling velocity use an average of recent velocities to work around bad input events. r=Cwiiis