sync compositor: pass simple gfx types by const ref

See bug for reasoning

BUG=159273

Review URL: https://codereview.chromium.org/1417893006

Cr-Commit-Position: refs/heads/master@{#356653}
void AwContents::RequestProtectedMediaIdentifierPermission(
    const GURL& origin,
    const base::Callback<void(bool)>& callback) {
  permission_request_handler_->SendRequest(
      scoped_ptr<AwPermissionRequestDelegate>(new SimplePermissionRequest(
          origin, AwPermissionRequest::ProtectedMediaId, callback)));
}

void AwContents::RequestProtectedMediaIdentifierPermission(
    const GURL& origin,
    const base::Callback<void(bool)>& callback) {
  permission_request_handler_->SendRequest(
      scoped_ptr<AwPermissionRequestDelegate>(new SimplePermissionRequest(
          origin, AwPermissionRequest::ProtectedMediaId, callback)));
}
