Convert plugin and GPU process to brokered handle duplication.

BUG=119250
Review URL: https://chromiumcodereview.appspot.com/9958034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@132303 0039d316-1c4b-4281-b951-d872f2087c98
void CommandBufferProxyImpl::OnEchoAck() {
  DCHECK(!echo_tasks_.empty());
  base::Closure callback = echo_tasks_.front();
  echo_tasks_.pop();
  callback.Run();
}

void CommandBufferProxyImpl::OnEchoAck() {
  DCHECK(!echo_tasks_.empty());
  base::Closure callback = echo_tasks_.front();
  echo_tasks_.pop();
  callback.Run();
}
