Merge "docs: New section explaining how to set the custom launch color of TV app" into mnc-docs

  design guide.

</p>

<h3 id="transition-color">Change the launcher color</h3>

<p>When a TV app launches, the system displays an animation that resembles an expanding, filled

  circle. To customize the color of this animation, set the <code>android:colorPrimary</code>

  attribute of your TV app or activity to a specific color. You should also set two additional

  transition overlap attributes to <code>true</code>, as shown in the following snippet from a

  theme resource XML file:</p>

<pre>

<resources>

    <style ... >

      <item name="android:colorPrimary">@color/primary</item>

      <item name="android:windowAllowReturnTransitionOverlap">true</item>

      <item name="android:windowAllowEnterTransitionOverlap">true</item>

    </style>

</resources>

</pre>

<p>For more information about working with themes and styles, see

<a href="{@docRoot}guide/topics/ui/themes.html">Styles and Themes</a>.</p>

<h2 id="tv-libraries">Add TV Support Libraries</h3>

<p>