QA:Testcase desktop volume

Description

This tests the basic volume management using keyboard/media keys on a desktop.

Setup

1. Go to HTML5 WebM test page or find some source of sound playing more than one minute.
2. Start playing any of the videos from web page above or from your own source of sound.

How to test

1. Use a media key on our keyboard to decrease the volume to minimum.
2. Use a media key on our keyboard to increase the volume to maximum.
3. Use a media key on our keyboard to mute the sound.
4. Use a media key on our keyboard to unmute the sound.

Expected Results

1. All the media keys should work as expected.
2. There should be some visual feedback after pressing media keys.