Handling volume up/down/mute keypresses within Chrome.

When Window Manager sends us a NOTIFY_SYSKEY_CLICKED message,
we adjust the volume accordingly.  Currently just calling
amixer as WM was doing before.  There will be a different
change submitted for WM to send this message instead of
calling amixer itself.

Patch by [email protected]:
http://codereview.chromium.org/2102001/show

BUG=cros/525
TEST=none

Related to issue 2107001.

Review URL: http://codereview.chromium.org/2107010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@47451 0039d316-1c4b-4281-b951-d872f2087c98
4 files changed