GitLab

RequestSupportedAttrs should fail when |text_input_client_| is
not available. Otherwise, we will see an access violation.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/23819038

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@222071 0039d316-1c4b-4281-b951-d872f2087c98