Reflect code changes in ui tutorial.
Reflect code changes in ui tutorial.

The seekbar color consts got moved from Controls
to ui.Constants.

Issue #2005.

Change-Id: Id8c09cb59930f2f23a350cb1e7be3c8708c121d7

tvoli/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player