Retrieve per host storage usage from QuotaManager.

R=kinuko@chromium.org
BUG=none
TEST=QuotaManagerTest.GetUsage

Review URL: http://codereview.chromium.org/8079004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@103921 0039d316-1c4b-4281-b951-d872f2087c98
QuotaManager* QuotaManagerProxy::quota_manager() const {
  DCHECK(!io_thread_ || io_thread_->BelongsToCurrentThread());
  return manager_;
}

QuotaManager* QuotaManagerProxy::quota_manager() const {
  DCHECK(!io_thread_ || io_thread_->BelongsToCurrentThread());
  return manager_;
}
