Volume slider value should be 0 when audio is muted
https://bugs.webkit.org/show_bug.cgi?id=120553

Reviewed by Eric Carlson.

Source/WebCore:

Fixed the problem of showing a non empty slider when audio is
muted.

Test: media/volume-bar-empty-when-muted.html.

* html/shadow/MediaControls.cpp:
(WebCore::MediaControls::reset): Use setSliderVolume.
(WebCore::MediaControls::changedVolume): Use setSliderVolume.
(WebCore::MediaControls::setSliderVolume): Added to set the volume
to 0 when muted and to its value otherwise.
* html/shadow/MediaControls.h: Added setSliderVolume.
* html/shadow/MediaControlsApple.cpp:
(WebCore::MediaControlsApple::reset): Used setSliderVolume and
setFullscreenSliderVolume.
(WebCore::MediaControlsApple::changedVolume): Used
setFullscreenSliderVolume.
(WebCore::MediaControlsApple::setFullscreenSliderVolume): Added to
set the volume to 0 when muted and to its value otherwise.
* html/shadow/MediaControlsApple.h: Added setFullscreenSliderVolume
* html/shadow/MediaControlsBlackBerry.cpp:
(WebCore::MediaControlsBlackBerry::reset): Used setSliderVolume.

LayoutTests:

Added test to check if the volume slider value is 0 when the
element is muted even if volume is set to something else.

* media/volume-bar-empty-when-muted-expected.txt: Added.
* media/volume-bar-empty-when-muted.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154944 268f45cc-cd09-0410-ab3c-d52691b4dbfc