Move chrome specific code from platform/audio/chromium to platform/audio
    
Re-factors chromium code to parent folder platform/audio.
Remove AudioDestination.h abstract class and rename AudioDestinationChromium* to AudioDestination*
Android code is moved to dedicated android folder.

Review URL: https://codereview.chromium.org/100993004

git-svn-id: svn://svn.chromium.org/blink/trunk@164305 bbb929c8-8fbe-4397-9dbb-9b2b20218538