GitLab

Add audio source files needed for PPB_Audio to build, and #ifdef out
host side code. Flesh out the SyncSocket and CancelableSyncSocket stubs
a bit more to compile and link.

BUG=116317
TEST=compiles

Review URL: https://chromiumcodereview.appspot.com/10412014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@138007 0039d316-1c4b-4281-b951-d872f2087c98