Add MEDIA_EXPORT for MacDesktopConfiguration::GetCurrent() to fix build break after r179218.

Review URL: https://codereview.chromium.org/12092031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@179237 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed