GitLab

webstore_private_api returns "already_installed" when an install request specifies an extension id that is either already installed or is in the process of installing.

BUG=222735

Review URL: https://chromiumcodereview.appspot.com/15292011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@203070 0039d316-1c4b-4281-b951-d872f2087c98